Having a "locking differential" needs a bit of clarification.
. On a part time 4wd 4runner the center differential is always locked when in 4x4
Maybe I am crazy as I have heard/seen this many times but in my mind a part time 4runner does not have a center differential. It is true that it ACTS like a center differential that is always locked but the transfer case has no differential in it vs. the full time 4x4 (limited in 5th gen) which as mentioned has a differential in the transfer case (center diff) that can be locked or unlocked
In a technical sense I believe you're correct.
I think we commonly (if mistakenly) refer to a gear box that has a single input shaft and multiple output shafts is a "differential". For example I would still call an axle differential a "differential" whether the internal carrier has a spool, a mechanical locker, a selectable locker, or simply open spider gears, although only one of those is actually a true differential.