If it were me, I would pull it completely down and inspect everything!
It only costs time and the price of a gasket set.
I bought an engine that looked great and had been rebuilt recently. Thought I was good to go. Pulled a piston and rod to be sure and the rings were broken in that cylinder...and the next...and the next...
Would have been a PITA had I installed it as-is. Apparently someone didn't know how to install pistons with a ring compressor.
I had a 383 like that. It ran ok, but had a weird noise in it. Pulled it down and the cylinders had never been final honed, and all the rod bearings were worn out. "Just rebuilt".
Just me, but when I buy a motor/trans I always look at it as needing rebuilt, even if it comes from a friend.
