Your Model 29-3 dates to about 1987. Member Kernel Crittenden can probably narrow that down to month.
Production and Engineering Changes:
-2 (1962) Cylinder stop changed, eliminate trigger guard screw
-3 (1982) Eliminate cylinder counterbore and pinned barrel with small change in in cylinder length to 1.69"
-4 (1988) New yoke retention system/radius stud package/floating hand: early models marked 29-3E for endurance package.
Your Model 29-3 dates to about 1987. Member Kernel Crittenden can probably narrow that down to month.
The bulk of the ship dates for this prefix are clustered very precisely in the date range of....
December 1987 - February 1988.
But at the time, blue 8 3/8-inch N-frames weren't exactly flyin' off the shelves. (I know. Hard to believe, right?). It may of shipped some months latter.