Very polished and then replated. The serial and reference will likely have been lost after that extensive a polish. The main timekeeping hands have been replaced too, they should be black edged.

All of those points will affect the value, and are worth pointing out to the seller if you still like the watch.

The Montreal is an interesting place to start a Heuer collection - it's quite tall and sits high on the wrist. Have you tried one on?