There's no reason they wouldn't work fine. You aren't removing any measurable amount of material by tumbling them. The bullets that are under the moly are no different than a bullet that never got coated.
I suppose, in theory, you might be able to create some sort of measurable difference in pressure with different corrosion or cleanliness of bullets and any amount of lube that might be on them but you'd need pressure test equipment to see the difference, I guarantee that.
Expect them to shoot exactly the same as the never-coated bullet of the same make.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.