RCEME Parkerized weapons during FTR starting in the mid/late 1950's onwards but it isn't that color. It's a dark grey manganese phosphate that was used and is a very nice finish.
That Mk.2 looks unfinished without baked Suncorite 259 paint on the phosphate.
---------- Post added at 03:07 PM ---------- Previous post was at 02:58 PM ----------
CAL switched to manganese phosphate in the 93L serial range. That would be at some point in mid to late 1950 if memory serves. Inglis pistols, Stens and Brens also sport the very nice dark grey Parkerized finish so it was being applied to other factory new weapons during WWII. I wouldn't be surprised that the chemicals were the same as used on many U.S. weapons. Wow, that would be a study in itself learning who produced and supplied the chemicals!
I wish I had 'em all back Buck!! The L42's too!!! I thought I was going to die with them. It's hard to believe the good old days have come and gone.