Well, I haven't shopped for too many Qjets for years. Picked up one last year completely restored for a friend's 67 350 and it was under $200.
You didn't ask about price (but you did say "should I buy it?), but I have to tell you, I was shocked when I saw what they were asking for that one. If you have a good one that is restorable, check with Eric at www.vintagemusclecarparts.com
restore it. OK, OK, I realize if you are looking for a numbers carb you probably don't have one to restore. I would still look around. They are out there.
Found this one by searching for 7029204: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=230671132285&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
It is only dated four days later. I realize that reserve has not been met, so can't say for sure what . Maybe these really do bring that kind of money.