This special production run came with Hogue finger groove grips, hence why mine above is sporting Spegel Boot grips. I see no real value in keeping newer guns "original" if they came with rubber grips, just my thing.
As for the production info, here's what Roy Jinks provided some years ago to collectors in a Special Products listing:
-Produde code 103591 - 4" bead blasted finish, blue, Hogue grips, April 1989, qty - 1969
-Product code 103592 - 6" bead blasted finish, blue, Hogue grips, April 1989, qty - 1995
Very nice gun!
BTW - I'm sure Wayne's comments are in the purest term 'positive', meaning you got a great deal, no-one is trying to suggest you are not honest.