Re-using Used Lifters on Another Cam

That's how every car was started way back when and still today. Bust it off an go. You think they were gonna take time to break in every flat tappet camshaft the oils back then had a higher zinc that left the factory? Not just no, but hell no. Of course, the oils back then had a higher zinc content, too. Most spring pressures were mundane to say the least.
And the lifter bores were closer to newly machined and the OEM lifters were made in the USA of quality materials and machined with pride! LOL