Bill has always used a hammered bronze 402. He has often mis-identified it as either brass or a regular 402, but I’ve been going to see him play since 1992, and it’s always been a hammered bronze 402.
Probably a 400 supraphonic but maybe a COB super. The 400’s are 5” deep, the 402 is 6.5”. Otherwise they are the same for a given era