A "-2" is a fairly old version, probably from back in the early 70s. The 3310 is up to at least "-12" now. That doesn't mean the old one is bad, but a lot of internal brass parts could be corroded, and small air and fuel passages clogged. Unless you're a carb guru, I think you did well to not get it.
A good place to look for Holley carbs is at their eBay store. They have very good prices on refurbished carbs. I suspect most are returned to stores like Summit Racing, who send them back to Holley for inspection and testing. I bought an 80457A a few years ago that looked brand new. It even came will all the accessories, and it worked just fine. All I had to do was a adjust the float levels a little.
I'm curious here. What kind are carb are you replacing? And is it for your 468?