Yes, but if you are looking for used ones, I believe the 4.56 ratio only came on certain 4Runner models and not Tacoma's, lowest ratio found on the Tacomas seems to be 4.30 (same 8" diff though)

I purchased a 4.56 one brand new from the dealer and retrofitted it to an 85 pickup, so they definitely exist.

Here is the Toyota part #

41110-3D010 4.56 electric locking diff