Good day.
For me unknown, is the Army using nowadays the same system as the Air Force.
Example
UH-60A 80-23453 (photo from mr Roland Bergman) http://www.airport-data.com/aircraft/photo/284496.html
Here you see the serial system only the number of the serial and not the fiscal year. I thought the 0 is placed on the helicopter when it is older than 10 years.
another example
UH-60A 81-(2)3604 (photo from mr Martin Flock) http://www.airport-data.com/aircraft/photo/556378.html
Here also (i thought) the 0 is from more than 10 years old and the rest is the serial not the first number 2 is the fiscal year.
UH-60L 00-26850 (photo from mr Andy Graf) http://www.airport-data.com/aircraft/photo/448783.html
Only the serial and not a 0 in front (younger than 10 year).
regard remco