To me, when it comes to flat-tappet cams, it depends on how much of a gambler you are with your time & $$. And how well you inspect your used parts.

I've spent hundreds to save a few $$ using this method.

For a low-$ refresh (hone) with rings & bearings or a swapmeet longblock it's down to your time and inconvenience when it goes boom. Anything more, I'd buy new.

I'll admit, I've bought several swapmeet deals, but I'm not inclined to put them in a fresh rebuild.