Capitan,
As far as production dates, there are no available records for such. Rough dates can be associated with the places where they were made.
Monson, MA 1970 - 1989
Palmer, MA 1990 - 1994
Norwich, NY 1997 - present
If your gun is a fixed barrel model, it was made in the latter part of the Palmer era if memory serves.
I don't know the model number on those guns, but possibly somone else does. I imagine that for internal parts, it is identical to a Model 14 357.
I don't know what the factory rated them, but I can't see that frame not standing up to +p+ 38's all day long since it is probably indentical to the 357 frame.
I hope that helps, and welcome to the forum.
Roll Tide