AY bought one used 340 from VS before they got new ones from Airbus. They replaced the seats in that one, so there's no practical differences with newer ones right now. No reason to avoid that one, unless you don't want to fly in an airframe from 90's. Some time ago AY also got two used 340s from AF, and didn't replace the seats nor the IFE. Those are ones to avoid right now.

However, the ex-VS bird will become undesirable in biz class next year since just recently AY announced that they won't put new full-flat seats into that one since it will be among the first ones to go (with ex-AF birds) once they get the 350s. But right now only geeks will notice the difference.