The older basses did not have the steel inserts under the tailpieces. I have had the brass screws on the tailpieces break before on a couple of occasions. Once while playing and the tailpiece came off, and on another bass, while it was in the case. I guess the brass just corroded, the screws at the wood surface were kinda green. I just got the broken off screws out the best way I could and replaced them with stainless steel screws. So, if you are removing an older tailpiece, be careful, the screws could break leaving you with part of the screw stuck in a hole in the instrument.