I've switched out take-offs and not had an issue w/ headspace.
I've switched about 7 -8 of them. All but one headspaced just fine. None had the stampings line up where they were supposed to be. A Shilen pre-fit is nice but they are $300. A brand new take-off can be from $25-$90 depending on caliber. They are also already blued if CM barrels.
I have a box of recoil lugs that are slightly different thicknesses. I can fit 99% of the Remington barrels to headspace fine just swapping lugs. I know a couple of 'smiths that do just that when I guy wants a cheap job done. I wouldn't leave a customer's barrel with the stamping not visible but no law against it.
I can't quote a price on it however as I don't do it for $.
