NO. It was usually on a stamp on a metal tag that was on the cover plate (depending on the years but after a certain year it was only on the build tag for the vehicle) I believe. No time like the present to get some fluid and a gasket and count though. The gearing is stamped on the ring gear when you spin it around. I guess if maybe you have one of those tiny endoscope cameras you might be able to poke it in the cover and rotate the pinion and see (not sure on that approach). FWIW, fresh gear oil is good for them if you have never been in there during ownership.
Also, if your vehicles are pre 1978 chances are you have a dana 44 though and not a 10 bolt (just looking at your user ID info) unless someone has changed them out.
