Upgrading by using older speakers

I have the opportunity to pick up two Mission 704's for an awesome deal but am weary due to them being older speakers. I currently have Klipsch B2's and the Mission towers by far seem to be a decent upgrade.

Should I avoid older gear or what things do I need to look out for if I jump on this deal?

Family deal. $200 for the pair.

So is this a good idea? Any help would be appreciated.

Looked at them yesterday and they are still completely clean. Basically have been in the house covered by cloth this whole time. I was thinking about taking them home and checking them out before I commit to anything, but since these speakers are from late 90's to early 00's it is hard to determine if this would be an upgrade or not.

Guess I just have to do the smart thing and take them for a test run.