IMO the last good Conns were made in the late 1950’s.  I can’t think of a 1980’s Conn worth that much.  There are better deals than that for tenors.  For example check out the Vito (Yamaha YTS-21) at:
 http://www.2ndending.com/saxes.html

The market is saturated with inferior horns made mostly in Asia.

The 1980s Conns are no better. I'm not sure where they were made, but they are not worth a 600 price.

Being able to play test a horn first should always be your first option.

So, look locally. Then buy what you like, even if it is a purple colored thin as paper asian horn.

Just enter Tenor Saxophone on ebay. Even go a step further and narrow your search down to instruments priced in the 200 to 500 range. You will see a lot of crap, but also a handful of Vintage American horns that are much better. They usually need a simple visit to the local repair shop for a freshening up. There are 1000s of them out there in homes where a student played for a year and stopped. A Bundy, Bundy II, Vito made in Yamaha, Yamaha any model made in japan, Kohlert Bixbey (rolled tone holes), any US made martin, Buescher, etc

It is a wonderful market for the player. Not such a good market for those of us with a thick inventory. In time, the inferior horns producers will fold. There are more horns than there are horn players right now. A buyers market.

Good Luck