The C220507 pistol has a welded base magazine with the chemical blue, which is considered to be a new production magazine after WWII.

The magazine might have had markings polished off of it prior to finish, but it doesn't show any sign of previous markings. It just looks like a new production post-war magazine with the same chemical blue as the pistol has.

The C236xxx and C237xxx serial ranges are well after (16000-17000 guns) where Colt's started post-war commercial production.
The magazine posted by LBB clearly has the pre-WWII commercial marking on the base. It is presumably a pinned base magazine, and although I can't say for sure from the photo, it appears to have an oven blued finish.
If it is pinned base and oven blueing...then it is pre-war production. Whether it is factory original to the pistols in the C236xxx and C237xxx serial ranges, I don't know.

I've heard of some other early post-WWII pistols manufactured in late 1946 and early 1947 as having pre-war type mags with them, but again, I don't know how to prove one way or the other whether they were the mags factory shipped with those pistols.