old PREMIUM aluminum skillet w/iron handle

This remains one of my favorite old (antique?) skillets -- pictured here the other day after I'd had it out to fry up some pork chops. When I first found it at a thrift store (20-ish yrs ago) the whole thing could have passed for cast iron (by color, if not weight) as it was most thoroughly encrusted with *years* worth of old black/brown grease/yada yada -- after many, many (many!) hours of scrubbing it finally emerged as seen here, made of heavy gauge (1/16" thick or so) aluminum with a cast iron handle. [most of the baked-on crud eventually scrubbed away...what remains gives it "character". ;-) :-) ] It measures 11-1/4" side to side across the 'pour spouts' and 18-1/4" long including the handle, and is 2" deep.

I cannot make out any more than the topmost portion of its maker's (?) information stamped on its bottom because it either wasn't stamped terribly deeply originally, has worn off over the years, or both. The top line clearly reads "PREMIUM" with "MADE IN U.S.A." under that in small type, then the next line appears to read "FREE WITH [X]2000 SET". There is at least one more stamped line, but I cannot make out any more than a "SO" (or "60"?) and "TO" (or "OO", or "00"?) from it -- maybe also a "N" below that from one more line.

I do not know if PREMIUM was its maker's name, or an indication that the pan was indeed a 'premium item' that one could earn after buying something else, or both. Does anybody know, or has anyone ever seen similar pans?? My research so far has not yielded a single clue... :-(