2016 at and mt ring gear sizes ?

So what size is in my 2017 sr5 4x4

 

Here is a question... I called a dealer and gave them my vin, they decoded it to say I have a 8.75" ring gear, 32 spline axles. Now, ARB lists the RD232 as the right rear air locker. The truck is a 2017 TRD Sport with MANUAL trans, which means I have 4.30 ratio, freakin great. BUT the dealer says 8.75" ring gear, ARB lists only 8.0" and 8.9"... same with certain Ring and Pinion sets, all say 8.9" if manual and 8" with automatic... I'm so confused about this crap. How do I figure this out WITHOUT tearing the thing apart!

 

Factory locker trucks (auto or manual) and manual (with factory locker or no factory) all got the 8.75 rear ended. Key point being manual trucks and factory locked trucks got the 8.75”. This only leaves one other combination, automatic trans w/no factory locker, these got the 8” rear end. Toyota said it’s a 8.75” ring gear, I don’t know if arb had a typo, they measured a different part of the ring gear or what. It’s the same thing.
https://eastcoastgearsupply.com/i-23993723-toyota-8-75-arb-air-locker-rd232-all.html

 

Yep. Now with research and talking with the dudes at ECGS (great customer service so far BTW!) I am throwing the idea around of getting the rear third member with factory e-locker and 5.29's - as that's $945 plus shipping after core. Since I'm going with 5.29's front and rear anyway, I am ordering the front diff from them and the rear as well, but I would have to make the rear elocker work... Just put up another post on this but logically I'm pretty sure this can be done and fairly simply, too... Hmmmmmm