If its worth it to you, yes. Prices are all over the place. Sometimes you can get lucky and get really good kit for virtually free, but you have to be in the right place at the right time. Compared to the new price (AG in UK lists it at £1500, so >$2000) $320 is a steal. I say, if it is complete and in decent condition, and you can afford it, go for it and be happy. Even if it's missing say a neg holder for a size you need, it's not a necessarily a deal breaker because you will be able to obtain (or even make) one. Just make sure all the main parts are there, and it looks like it has been looked after.
Thanks I will do some reading then. e seller is asking $320