Are these normal machining marks?????

[Luvlegs]

Popped open the diff last night - lo and behold - the gears are NOT what the axle codes indicated (3.73)....
the ring reads "3817778 11:4 GM 10-71 2" ....

Are the marks that look like teeth groves (to the right of the ring gear) normal? I wonder if it was prior damage that lead to the gears being changed....?? It's all nice and clean in there, no shavings, no rubbing, no binding, was very quiet when driven, no vibrations or anything noticable.

Also, compared to what I thought were 3.73s - what's this going to do to my mileage, take off, top end, etc.... I am working on a 454 right now to put in.... eventually, go to posi when I locate one.

Thanks for any input.