Some came with 4.88's according to something I read, it said a few came with odd gearing & it was unknown why. I wish I could remember where I read it I'd provide the link; I'm 99.99% sure mine is stock & average but I'm going to check the codes to be certain. I have 31's on it right now; it had them when I bought the truck. Once I figure out the gear ratio I'll decide what to do about tires since it needs them right now.
I also have a little sag in the back & the shocks are starting to boat back there so it's time for new shocks in the back & I figured I'd put in a set of springs while I was at it. I put Bilsteins up front just after I got it because it had a broken shock on the pass. side. I have read that NAPA springs are good to level these back out but they don't have a heavy duty version & my 4Runner will be used a few times a year to deliver mail on a rural route (wifes a rural carrier) so there will be a load in the back occasionally, that's why I'm not sure what springs to use, I wouldn't mind a slight 1" - 1.5" lift but I'm not sure if it'll look right without lifting the entire thing & the whole cv wear thing. If I do lift the entire truck by that much, then 35's will be an option...but I'm still new to 4Runners & Toyotas in general so; I'm still in the dark & looking for the light switch!