So my front brake rotor is pretty grooved, and the outside portion of the rotor seems to be loosly connected to the inner structure. 

I was bopping around Ebay and saw used later model brake rotors.  So my question is will a 2002 rotor be a direct swap on my 92gs?

Yea rotors are the same, you dont even swap it with the 10 or 12 rivet carriers, you swap it with the hat. Just unbolt and bolt the new one on.
Here is the word of caution though ... they can be thinner than they should be as per the book and still not be grooved. In fact they are barely a few 1000's over 4mm new. So very very easy to get em under that 4mm threshold and still look great. Now I have run em thinner than 4mm without problem. How much thinner ... I am not sure, but a few 1000's under, easy, more = risky, it can break, or get your pistons so far out they can bind and not go back in.
Cool.
Buddha.

Got it.  THX Buddha.  I'll give it a good micrometer check before I throw it on.

See if you can before you ebay it. Once you pay for it ... what is the point, might as well put it on.
There was a guy wanting to buy one off me. I have 5 rotors and not 1 worth the cost of shipping.
Pay for shipping and I'll get the cleanest, thickest one off to you... but I am not inclined to run it on my bike, so I am not really going to sell it, or stand behind it, or even claim to know you if its a POS.
If yoi're getting a good ebay one, just go with that one. You may luck out, see if you can get a low miler. The rotors last about as long as the tire if you're agressive and run the high friction pads.
Cool.
Buddha.