I might have missed something, but I don't see the manufacturer of the receiver. Is it a USGI or a commercial brand (Plainfield or 1st gen Universal)?? That's where the S/N is and that's the important part if it's a USGI. It determines date-of-build (not the barrel date if there is one).
This may or may not be a German/Austrian return, these may have the last 4 digits of the S/N stamped on the bolt, and/or stock, and might have another symbol on the heal of the stock (actually a stag horn). Most of these are mixmasters, but some can have mostly matching parts. Not all of these have the notched rear sight. FN in Belgium did a major arsenal rebuild of US rifles just after the war, and this was most likely the source of at least some of the German carbines. FN did not stamp the stocks as rebuilt.
Most USGI carbines (but not all) came out of their respective wartime factories with matching parts, and parts went thru a design evolution based on combat experiences and field failures. Type II and III windage adjustable sights were on Winchester, Inland, Rock-Ola, Saginaw Gear, Std Prod, and IBM carbines towards the end of WW 2, where bayonet lugged barrel bands were post war (although some evidence indicates some might have made it to the Pacific in 1945 on M2's)
A great number were arsenal rebuilt post-WW 2, and became the "mixmasters", as original MIL-SPECs required interchangeability of parts from various makers. Stocks were stamped as such, such as AA or RIA, usually on the right side behind the grip portion.
Springfield made parts post war, right up to 1967. I have an ex-ARVN Inland with SA51 barrel and a cast SA trigger housing.
If you got this for an equivalent of $550, then you did quite well if it's a USGI receiver. Enjoy shooting it!
