Lay down Sally...

No problem, in fact every Mag and La I every rebuilt required turning, if you don't oil pressure will be low.
My guess is as motor get older, people neglect them, not as frequent oil changes, or run them low on oil.

If it makes you feel any better the crank in my 48 Willy's is .040/.040 rods and mains.
No more turning on it, and you cannot buy one.