The Germans did not mark their captured weapons in such a way. At most, it would have a Depot stamp on the bottom wrist of the wood stock, not the metal (ie: Kru1) Most of the SVT40s captured by the German forces were simply pressed directly into service.
BUT.... those funky ReichsAdlers that are stamped on a few of the SVTs that are in Canada are odd, as they came out of the crate that way. Know of a couple that came directly out of a crate from a dealer that way, and quite certain the dealer didn't do it, as they were normal price.... but then that would leave the only other option of it being done during refurb or in Ukraine where they were stored, but by whom and why? As they didn't have a premium price when they were initially sold, that seems to rule out fakery for monetary gain, but still...
John from Marstar sold a few M44 Mosins with these exact same ReichsAdlers and I believe they came out of Yugoslavia, and John swears that he found them in the warehouse that way, and didn't pay any premium either I believe.
Since the fake Nazi stamps have been around since WW2 ended, my guess is some bored and/or drunk factory workers having some fun???