There are several boxes from the F-bodies, but the two in question are the 12.7:1 quick ratio steering boxes that were available in the '82-'92 Camaros (WITHOUT "Soft Ride Suspension"), such as the Z28. On each box, the factory stamped, in ink, a two letter code on the end of the box. The QR boxes were "WS" and "XH".
IIRC, the WS box steers 35 degrees, where the XH box is 32 degrees. The QR G-body boxes from Grand Nationals and such, are 39 degrees. So, they are fairly close.
I wound up getting a QR box from an '89 Z28, so we'll see how it works out.