hard to tell, but to me it looks like your back is just "varnished" & your belly (the brown stuff) looks like "toxhorn" (bakelite/phenolic).
in their no. 3 catalogue (1950? - with no bow pics),
the earliest I've seen they offer huntings bows yew, osage or lemonwood
with "recurve ends" .... it seems only on osage bows.
I can't tell if thats osage on your back or waht your other 2 lams before the belly are ....
....they don't seem to mention "laminated" bows, but ....
Could that be rawhide on the back? ....it goes clear doesn't it when applied & treated?
In the No. 6 catalogue (1953?) they mention "toxhorn" facing (belly) & laminated cores but their pics do not show "static" or "stuck-on" recurves (they show semi/hybrid & real recurves ).... so maybe somewhere between in catalogues no. 4 & 5 might be the answer? ;-)