tournament. It's hard to argue against them getting the auto-bid right now. I have them getting the auto-bid in my bracket, but I also have them behind BYU in the S-curve. If I would've assigned SDSU the auto-bid then I'd have Boise State as my last team in (and BYU would be bumped up to my 3rd-to-last team in).
You are right that many bracketologists just put the current conference leader as getting the auto-bid. Others use other methods. I personally project who I think will end up winning the regular season. Either way it's not that big of a deal because there's no way to know for sure who will get the auto-bids until they actually win their conference tournaments and it doesn't really affect seeding of the at-large teams (unless there are bid thieves that bump teams out of the tournament).
SDSU does have a pretty solid resume. They are 25th in the RPI with and SOS of 70 and a non-conference SOS of 70. Pomeroy has them rated 29th. All of those are solid numbers and would be indicative of a 7 seed. Add to that the fact that they have 4 RPI top-50 wins - 2 of which were on a neutral court - and only 2 losses to teams outside the RPI top-50 and they should be a very solid at-large team. I think a 7 or 8 seed is appropriate for them right now. So long as they don't lose in the MWC quarterfinals they'll end up with no lower than a 9 seed IMO.