Detroit locker posi unit??

i have a new one in the box with tags wrapped in plastic saying saying LS-325 b assembled by nov 3 1972 z,,,,does anyone now what that would be to...thanks

I have used the d locker in a 600 horse p/u, w/ absolutely no problems. just don`t goose it in a turn. and my friends it is great on the dragstrip. seen spools break, posi`s and limited slips go out, shelled rear gears( afew of my own before we went to a dana 60) have never seen a locker break in a ford or mopar! they are strong! just fyi "ps, pull that puppy out and send it to me) will pay the freight-----bob