Hi Aaron,
Those were pretty standard patent / licensing plates at the time. You can see the remnants of the mention of Radio Corporation of America (RCA) on it also. RCA and GE owned many of the radio patents at the time and a company had to get a license from them to use those patents to build radios.
It's unusual to have burned out filaments on 6V tubes. Maybe someone stuffed bad tubes in the set before you got it. The 6U5 has been an expensive tube for quite some time. It isn't needed for the operation of the radio but it does add to the aesthetic appeal.
You might try this version of the schematic. It's slightly better but still not great.
https://www.tubesandmore.com/sites/d...c_me_pg8-1.png