I don't think that is a Wyoming Highway Patrol gun.
As I recall they had the number on the other side of the frame in smaller font.
They were no dashes and came with Target grips.
They only had the 66's for a short time.
They got them about 1978. They issued, and practiced with 125 grain mags. I heard they shot the guns loose in a short period of time.
They then went to Berettas and after that I heard they had bid on a bunch of Sigs, but that was many years ago.