Parkerizing on a No4?

[Ridolpho]

My late Mk II has very black suncorite which I believe was done on top of a parkerized surface. I know it's original as it was in a paper wrapper prior to my purchase of it. I believe I've seen comments on this forum that late LB's had a parkerized finish (ie without paint)? I have seen a parkerized finish on WW2 built/refurbed Australian rifles that is very light green (like many 03A3's). Getting a handle on all the possible "genuine" new built/ FTR'd metal finishes is challenging.

Ridolpho