Replying to Buying used pivots/fks

Currently scouring second hand sites to find good deals on used pivots/fks bindings. Obviously these bindings are fairly sturdy so hopefully shouldn’t break down assuming they’ve not been neglected but what sort of things should I be looking out for/asking the seller to make sure I’m not buying duds (assuming the seller is honest)? The pair I’m looking at atm are pivot 12s if that makes any difference (in very dark blue if anybody can help me narrow down the year based off that, looks to be the newer turntable system)