The Winchester 7.92 ammo should be NCNM.
All of the regular American commercial plants had converted to NCNM priming well before War Two.
That said, I don't know what primers they would have used on US military ammo(likely the horrid FA-70), but they would have used their own NCNM primers on ammunition for foreign sales.
It was only the Army plants which stuck with that FA-70 corrosive primer. The US military only got rid of the corrosive priming completely late in 1953. The ONLY exception was with .30 Carbine ammunition, which was ALL NCNM, right from Day One.
In Canada, the situation was sort of half-and-half with the Government plant (DA) using corrosive, mercuric, huge Berdan primers and commercial and Crown Corporation plants (DC and DI) using noncorrosive, nonmercuric regular-sized Boxer primers. Ammunition made for sale to the US was loaded with NCNM primers, which makes the Canadian-made VCC 45 the ONLY batch of NCNM .30-06 of WW2.
But THAT batch of 7.92 should be okay.
Hope this helps.
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