Interestingly, the two transmissions had fifth gear failures differently.
My 1992 definitely chewed up the teeth on the syncro sleeve like most people. I only drove one <300mi trip home after failure, and only tried putting it in fifth gear a few times before just deciding buzz down the rest of the way in fourth gear. The damage happened in short order.
The other transmission must have been an early 1991 production. The teeth were all fine, but the brass-colored syncro hub only was a different design that only had two tiny edges of internal splines that got mangled. Rounded everything off to the point that fifth gear syncro could freewheel independently. Needle bearing was different, too, confirming that this one was made before the mid-1991 fifth gear update.
Fifth gear has been revised more than once on the SE-R. Ha, we're a rainbow coalition of weaksauce RS5F32's.