Welcome to APUG
Where did you learn to be a "Detective"
Yes you're right that Agfa Ansco changed the 103 developer formula from a Universal Film/Paper developer to a Paper developer between 1938 and 1941 by dropping the amount of Sulphite.
We don't know quite when this change came into effect commercially as the company changed the pre-packaged developer too. So this potentially widens the possible age of the paper.
Agfa Ansco wasn't taken over by the military, initially the US Treasury, then the Enemy Aliens Commission, the camera plant was turned over to making military equipment, but paper & film was probably sold for both consumer and military use.
Brovira being a Bromide paper has a better chance of still being usuable, but don't expect to much
MAybe some extra bromide & Benzotriazole in the developer might help the contrast if there's some slight fogging.
Ian