That is a very old blade, obviously. But the data stamped into blades are the blade serial number, the blade DWG(drawing number) basically the configuration of the blade so that blades are not interchanged with other blades that may seem or look alike. Hard to tell what maker it is but I'd say Hamilton Standard, most props have been that brand not all however. Aeroprop, Curtis electric, and to a lesser degree for smaller props Hartzel have been around for some time. But I'm going with HS. You might want to get into HS's companies info, they may be able to help. Almost no blades are perfect in their casting or grinding they are almost all either overly efficient or under efficient so there is a stamp on the blade which can be confusing because it has to be taken into account when adjusting blade angle at the depot level. That stamped number on some brands means that you are directed to correct the blade angle as much as the stamp requires accordingly . Other brands tell you what the blade is and you compensate ie The blade says - .02 so one would compensate and adjust it + .02 of a degree. On other brands it is telling you to adjust it -.02 of a degree. If someone jumps on my about 100ths of a degree or minutes of a degree, I'm trying to keep it simple to understand.