If my memory servers, the 2000 had 2 sets of idlers plus the rear boggies. But Polaris sold/sells auxiliary idler kits and I think the rails were even drilled for additional ones up towards the front. So likely whomever owned the sled put additional ones on, probably because they rode in low snow or road trails. It wasn't uncommon for people to pull all the idlers off and just run scratchers instead.
2000 700s were good sleds. Just the normal service stuff to check, chaincase oil ands tuff like that. It isn't uncommon for "older" Polaris sleds like that to develop an oil leak in the bottom of the oil bottle. The rubber grommet that the oil outlet fitting pokes in gets hard and starts leaking. Easy fix, just be aware that if you see oil dripping that is likely the problem.
sled_guy