The rear axle assembly that I replaced on a 1998 Chevrolet K1500 truck had those numbers stamped as
11-41 on a much older 1989 wrecking yard find. 41 ring gear teeth divided by 11 pinion teeth = 3.73 to 1 gear ratio. The glove box RPO code and the axle tag/stamp also matched. Had to check those first due getting under a wrecking yard pickup for further information can be unsafe due to they usually are not too stable. Squished parts pickers don't survive. Since as I recall a 3.42 to 1 gear ratio on my 1995 K1500 had the same amount of pinion teeth it wasn't a sure thing by just looking at the RPO code, axle tag, and by counting the pinion gear teeth after removing the pan. Needed to rotate the ring gear to see the stamp which took some additional time to properly lift the truck. Gears can be swamped out for different ratios and so it was best to be careful on getting something wrong installed.