A58.1-1945 and A58.1-1955, published by the National Bureau of Standards, both require partition weight to be considered "in office buildings or other buildings where partitions might be subject to erection or rearrangement... unless the specified live load exceeds 80 pounds per square foot". So that standard requires partition weight to be considered but offers no specific (e.g., 20 psf) requirement for the load to be applied. The 1948 Southern Building Code in Chapter XII requires a 20 psf dead load partition allowance. I don't have a BOCA code from that era. One can likely be purchased, however, at a reasonable price from ICC.