Used pistons, does anyone save them?

[36coupe]

I have a friend that is looking for used mercury pistons. He is in his 80s and builds, freshens up old flatheads. Being north of the border it cost a small fortune to buy new ones. He has a few mercury cranks and no pistons. When he scraps old engines he will save valves and guides that are in good condition along with cams for future builds. He prefers original oil pumps.
He refers to the pistons as seasoned.
This way he keeps costs down and it reflects in pricing.
I’m sure this might be controversial to some people. Not everyone has 10 K to build a new engine with everything new.
He actually has an 8ba 239 new pistons cam and crank bearing for less than 4K usd. He is 5 minutes from Maine