Yep, the kits are the same. GM did some minor differences between the V6 and V8 700r4. For instance, in one spot, the V8's got a thick sprag, but the V6's got a thin sprag and a spacer! The V8 also has a couple more clutches in its clutch packs, but everything will go into a v6 700r4. In fact, you can't find a rebuild kit for a V6 700r4, they're all engineless 700r4's.
If you want a generic "non performance" rebuild kit, which is probably what the guy put into my trans, you can find one at
http://www.expressautoparts.com - carparts.com used to list one, before they merged with JC Whitney, so I imagine it's also at Express.
And $250 wasn't just the kit, I think the kit was $80, fluid pump was $60, torque convertor was $80? Something like that? Yes, you should replace the torque convertor when you rebuild a trans. Once metal filings get inside a torque convertor, they can't be removed unless the TC is physically taken apart- and then it can be cleaned, then welded back together. The TC on mine is a remanufactured one (opened, checked, cleaned, reassembled), and the old one was a core.