Model 94 with flat ground calliper hinge pins?

I was recently looking around and saw a pair of S&W model 94. Not all that rare but something aout them caught my eye. That was thye pin for the bow/calliper. What caught my eye is they were flat, they didn't have the raised rivet/cap that I've seen on others they appeared to be flat ground at the factory. This particularly caught my eye because when I was a young teen and a pair of 94's lock jammed ( while they were resident on my wrist!) this was how I got out of them, by taking apart the hinge pin and cap and slipping appart the asembly . What IU'd like to know is which generation of the model 94's had a flat ground rivet instead of the pin and cap?

Edri

never mind, answered my own question, looks like these are the thrird ( and final) generation.

Edri