Isn't the transmission number printed on the upper tranny housing, which needs to be replaced to prevent snap ring failure? That's what I've been told. If the transmission number on the tranny housing is within the snap ring range, that should imply that you are not in the clear. That's what I've been told.
My '92 had the snap-ring problem "fixed" by the previous owner at ~60,000 miles, but the tranmission number on the top of the transmission case is within range (and the receipt for repairs does not list a new upper transmission case), which suggests that the upper transmission housing was not replaced when it should have been. Almost 30,000 miles later, I haven't had any problems, but I've been told that I should expect it to fail again eventually unless the upper tranny housing is replaced.