The N-numbers on the HU-25s were during their tests with the USCG before they received official numbers. Here is Baugher's list of the original N-numbers, but I think his first one is in error and is possibly N1045F as the photo, since there are no other aircraft with that Registry in his list. I'm taking the N1945F as a typo for N1045F:
2101/2141 Dassault-Breguet HU-25A Guardian. Coast Guard version of Mystere 20 business jet marketed in USA as Falcon 20
2101 (c/n 374) had test registration of N1945F. To HU-25B. Scrapped hulk at Coast Guard Aircraft Repair and Supply Center, Elizabeth City, NC. Report dated Feb 2009 suggest that fuselage may be at Aviation Technical Training Center, Elizabeth City, NC
2102 (c/n 386) had test registratin of N149F. To HU-25D. TO AMARC as 410010
May 1, 1995. Retored to active service May 5, 1999.
2103 (c/n 394) had test registration of N178F. To HU-25B. WFU. Used for support
of testing at Sandia Labs, NM. Reported Feb 2009 stored at Alberquerque IAP.
2104 (c/n 390) had test registration of N173F. To HU-25C
2105 (c/n 398) had test registration of N183F. To HU-25D. To AMARC as 410011 Jul 1, 1995,
restored to active service Jul 7, 1999
2106 (c/n 402) had test registration of N187F. To AMARC as 410007 Apr 7, 1995.
Still on AMARC inventory Jul 1, 2008
2107 (c/n 409) had test registration of N497F. To AMARC as 410018 Sep 4, 2001.
Still on AMARC inventory Jul 1, 2008
2108 (c/n 405) had test registration of N405F. To AMARC as 410015 May 27, 1997,
returned to service Nov 3, 1999, back to AMARC as 410016 Aug 10, 2001.
Still on AMARC inventory Jul 1, 2008
2109 (c/n 407) had test registration of N406F. To AMARC as 410012 Jul 11, 1995,
to Coast Guard Aircraft Repair and Supply Center, Elizabeth City, NC Jan 4, 2000.
Strapped hulk still there.
2110 (c/n 411) had test registration of N408F.
2111 (c/n 413) had test registration of N410F. To HU-25B. Hulk sunk as artificial
reef off North Carolina May 3, 2006
2112 (c/n 415) had test registration of N413F. To HU-25C+, later to HU-25D
2113 (c/n 417) had test registration of N416FJ. To HU-25D. To AMARC Apr 6, 1995 as 410006.
Restored to active service Feb 18, 1999.
2114 (c/n 418) had test registration of N417F. To HU-25D. To AMARC as 410014 Jul 25, 1995.
Restored to active service Mar 31, 1999
2115 (c/n 419) had test registration of N419F. To AMARC as 410017 Sep 4, 2001.
Still on AMARC inventory Jul 1, 2008
2116 (c/n 420) had test registration of N420F. Converted to HU-25D.
To AMARC as 410005 Apr 25, 1994. Still on AMARC inventory Jul 1, 2008
2117 (c/n 421) had test registration of N422F. To HU-25D
2118 (c/n 423) had test registration of N423F. To HU-25B
2119 (c/n 424) had test registration of N424F. To AMARC Jan 19, 1994 as 410002. Scrapped 2002.
2120 (c/n 425) had test registration of N425F.
2121 (c/n 431) had test registration of N429F
2122 (c/n 433) had test registration of N432F. To HU-25B. To AMARC as 410020 Sep 7, 2001.
Still on AMARC inventory Jul 1, 2008
2123 (c/n 435) had test registration of N433F. To AMARC as 410003 Jan 19, 1994.
Scrapped 2002.
2124 (c/n 437) had test registration of N435F. To AMARC Sep 26, 2001 as AC410022.
Still on AMARC inventory Jul 1, 2008
2125 (c/n 439) had test registration of N443F. To AMARC as 410023 Jan 24, 2002.
To HU-25B. To NASA as N523NA May 28, 2004. Reassigned to USAF Electronics
Systems Command Mar 2006. To civil registry as N448TB
2126 (c/n 441) had test registration of N445F. To HU-25B. To AMARC Sep 26, 2001 as AC410021.
Still on AMARC inventory Jul 1, 2008
2127 (c/n 443) had test registration of N447F. To HU-25D. To AMARC Jul 15, 1991 as AC410001.
Restored to service Sep 3, 1999
2128 (c/n 445) had test registration of N449F. To AMARC Jul 20, 1995
as 410013. Returned to service Sep 3, 1999
2129 (c/n 447) had test registration of N455F. To HU-25C+, later to HU-25D
2130 (c/n 450) had test registration of N458F. To AMARC Apr 25, 1994 as 410004.
Still on AMARC inventory Jul 1, 2008
2131 (c/n 452) had test registration of N459F. To HU-25C, later to HU-25D
2132 (c/n 454) had test registration of N461F. To AMARC as 410019 Sep 6, 2001.
Still on AMARC inventory Jul 1, 2008
2133 (c/n 454?) had test registration of N462F. To HU-25C+, later to HU-25D
2134 (c/n 458) had test registration of N465F.
2135 (c/n 459) had test registration of N466F. To HU-25C, later to HU-25D
2136 (c/n 460) had test registration of N467F.
2137 (c/n 462) had test registration of N470F. To AMARC Apr 10, 1995 as 410008.
Still on AMARC inventory Jul 1, 2008
2138 (c/n 464) had test registration of N472F. To AMARC Apr 13, 1995 as 410009.
Still on AMARC inventory Jul 1, 2008
2139 (c/n 466) had test registration of N473F. To HU-25C+, later to HU-25D
2140 (c/n 467) had test registration of N474F. to HU-25C+
2141 (c/n 371) had test registration of N1039F. To HU-25C+, later to HU-25D