What model speaker is this with single D123 driver?

I've lurked here off and on for years and have a few 'modern' JBL's, but my excuse to sign up and post is this pair of vintage speakers from a local thrift store. The aluminum dustcap caught my eye first, and then the JBL "signature" logo sealed the deal. The cabinet measurements are 19 3/8" x 23 7/8" x 15 7/8". The walls are almost an inch thick, and the front grille is recessed about two inches. The D123 driver labels say 16 ohms. One works fine (or what one might expect for a full range 12-inch speaker!), the other has an open voice coil. The front, sides and top are finished. The back is painted black and has two screw terminals. The bottom is unfinished and has four threaded holes, obviously for legs. I don't see any writing or label anywhere on either cabinet, just on the driver label and of course the logo/tag on front. Looking at what cabinets the D123 went in and looking in the registry, this appears to be a C38 Baron, but it has two blocks painted black where the tweeter goes. All the pics I've seen are of two-way speakers with crossovers. Was this model made in several configurations? Attachment 55591Attachment 55590

Welcome.
You didn't look hard enough! The C38/36 came ready for several loads. Certain ones, like this, required adapters which blocked off the unused holes and/or made the 15-inch hole work for the 12-inch woofer. Check the various loads available for the C38/36 here:

Attachment 55593