Two of the USRA cars were painted yellow in 1954. The numbers were 4576 and 4795. Both were used in captive service on the TH&B, not in interchange service. This info is found on the Westerfield data sheet entitled GTW/TH&B USRA Variations that is in the Westerfield kit box. I have the kit but have not built it yet.
Also worth noting, the USRA cars were repainted in 1950 and given the pennant logo and eight-sided ampersand. Originally the cars did not have the pennant logo and had the regular ampersand.
Only reason I knew there were two is because on Facebook Rapido was alerting potential customers that reservations for the Yellow TH&B cars far outnumbered reservations for all others and alerting people that were only two of the yellow & black cars.