Thank you all for the replies and wealth of knowledge captured within them!
I just chatted with my uncle last night and despite his age he recalled a few tid-bits about it.
Per him:
It's not the super-long barrel so probably the 4 incher, nickel plated, adjustable sights "and not all of them had those so that's nice" he says.
357, not 38, and should be manufactured either 1964/1965 or earlier as that's when he started on the force and it was his original sidearm.
I still won't see it until next week (he's not technologically inclined enough to take a pic and email me, sadly) but I'm getting more and more excited, especially with all of this great input!
Thanks again.