Some clarification here. I hope it helps :?
c/n (msn) 5051
Jeststar-6 (series 6)
N9217R oem
N400KC 1965-00-00
N44MF 1977-04-00 Harry Fergusson Inc De Moines IA
N31S (ca.1981) Elmer W. Glause Sr
N310AD 1982-05-00 Elmer W. Glause Sr
N310AD 1982-07-00 Modern World Export Finance Company
N310AD 1985-10-00 Mako Marine Inc
N555BS 1986-08-00 Mako Marine Inc
N555BS 1989-05-00 Alpha Air Inc
N555BS 1989-07-00 Marilyn Bateman
N555BS 1992-07-00 J. R. Staples Aircraft Sales
N488JS 1993-02-00 J. R. Staples Aircraft Salea
N488JS 1995-12-00 Sound Corporation
N488GR 1996-11-00 Sound Corporation
N488GR 2003-00-00 (wfu-stored KSFB)
N488GR 2006-07-26 Avion Jet Center LLC (stored KSFB)
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c/n (msn) 5210
Jestar-II (series 2 / -25)
N5536L oem
N400KC 1977-00-00 Kimbery Clark Corp Meena,WI
N707WB 1982-07-00 First Interstate Bancorp (Western Bancroft)
N787WB 1994-03-00 First Interstate Bancorp
N787WB 1995-06-00 Banair Inc
N787WB 1999-02-08 W. H. Barrett Turbine Engine Company
N787WB 1998-11-27 W/O Austin,TX (NTSB Id FTW99LA045) Landing-accident/substantial damage-NOT repaired
N787WB 2005-12-00 Support Group, Conroe, TX (fuselage in warehouse-stored /parts supply)
I believe your Jetstar seen/photographed in 1978 was c/n 5210
John