Found A Gun Lying On Ground Outside

[UPDATE] I called and anonymously reported it. For everyone saying “oh it was probably used for a crime”, while that could possibly be the case, it's very unlikely... It was found in an American Legion (sort of like a VFW) parking lot that is very active. It’s not like I found it in some shady abandoned parking lot. There’s people that come in and out of this building every day. It’s very likely that someone just dropped it getting into their car after a few drinks (found the gun around 2amish). Police have since come by and grabbed it. My main motivation for turning it in was just that I don't want to be caught with a "stolen" or lost gun.

So I guess my question is: Is it legal for me to keep it?

It's not a ghost gun, the serial number still on side. Found in the parking lot while walking outside, full mag (not chambered). I live in Pittsburgh, PA

I do not need moral advice either, I just need a strictly from a legal perspective. Also if it is reported lost (wouldn't be stolen because I didn't technically take it from anywhere) is there any way I can check to see so I COULD turn it in if need be?

Thanks