The receiver appears to have been Parkerized, probably during a rebuild; the original color would have been a deep oil-blackening.
The Army recognized the brittleness problem early (see Hatcher's Notebook) but given its rarity and randomness chose not to recall and destroy millions of dollars worth of rifles that rarely failed with good quality standard ammunition. But they did order that single heat treated ("low number") receivers not be used in arsenal rebuilds. When they came in to the arsenals and depots, the receivers were scrapped. But during the early days of WWII, the need for rifles - any rifles - was so great that that practice was stopped and those receivers were used in rebuilds. That is probably what happened to that rifle.
There is no point in having the rifle checked by anyone. There is no non-destructive way to know or see whether a given receiver is brittle or not.
I strongly recommend that you remove that butt plate, determine how much damage the stock has sustained and either replace the stock or at least replace the buttplate, preferably with the proper smooth one.
Jim
The Army recognized the brittleness problem early (see Hatcher's Notebook) but given its rarity and randomness chose not to recall and destroy millions of dollars worth of rifles that rarely failed with good quality standard ammunition. But they did order that single heat treated ("low number") receivers not be used in arsenal rebuilds. When they came in to the arsenals and depots, the receivers were scrapped. But during the early days of WWII, the need for rifles - any rifles - was so great that that practice was stopped and those receivers were used in rebuilds. That is probably what happened to that rifle.
There is no point in having the rifle checked by anyone. There is no non-destructive way to know or see whether a given receiver is brittle or not.
I strongly recommend that you remove that butt plate, determine how much damage the stock has sustained and either replace the stock or at least replace the buttplate, preferably with the proper smooth one.
Jim