The weight is correct for the LR AWD, i guess there is a chance the new LR RWD being offered are actually software locked AWD, but i think more likely it is a copy paste error.
The MR weight hasn't changed since it was released, if the pack design has changed it is possible they just forgot to update it.
For SR+ though, the weight is a completely new number added to the system. It's hard to see how they could easily have got this number wrong, and this number alone validates my whole analysis regarding the fixed battery pack weight.
SR weight was also increased to 3,627lbs from 3,549lbs before Thursday. Again it is possible this was a copy paste error from SR+, but given it was deliberately updated I think that's maybe less likely.
So in summary, I'm pretty confident the SR+ weight is correct and hence the SR+,MR and LR all use exactly the same pack structure. For SR there is some possibility the weight is completely wrong - it could be that it is not actually software locked and does already exclusively use a new pack design.