350 cam bearing interchange?

Yep, I HAVE done it that way a couple times, but as you mentioned, I had removed the casting flash years before, so I was LUCKY.
Even at that its a slippery slope doing it in the car, OR with the crank AND rods in place, you have to load the bearing onto the tool through that opening

 

Like a n00b I put the crankshaft in before i test fit the cam, and I am too lazy to remove it, clean all the lube off of it, re lube, etc etc, so I taped up the rod journals and just knocked the bearings out turning the crank when needed. I however do not have the rods and pistons installed. At this point, with your engine out, might as well take it all the way apart. New bearings, hone/bore, re ring it, etc. It will make it easier. Plus you'll never know if you're down to the copper until you look.