Correct tool to '77 3/4 ton 2WD rear axle bearing ring nut?

I'm repairing the rear brakes on a 1977 Chevy 3/4 ton with a 10.5" pumpkin and full float axles. The rear drum is secured with two identical ring nuts. They are 2.5 inches in diameter and have 6 slots in the ring. The Haynes manual shows a special socket that is used to tighten them. The socket looks very similar to one they sold at the parts shop that is supposed to be used on 4WD axles. I test fitted the ring nut to the 4WD socket. The socket is about 1.5 to 2mm larger larger than the ring nut.

Question: Should I be looking for a 2WD rear axle nut socket, or does this 4WD socket work for 2WD 3/4 tons as well? I did not think it fit as well as it should considering the amount of torque that is supposed to be applied to the outer ring nut - 250 lbs-ft. per the Haynes manual, but this was for 1988 - 1999 trucks. They did not have a manual that covered 1977 trucks.

Here's a link to a tool that looks identical to the one shown in the Haynes manual:

And here is the tool they have in stock at the parts shop: While I'm at it, the procedure per the Haynes manual for reinstalling was to tighten the inner ring to 50 lbs-ft. while turning the drum, then back off 1/4 turn, then re-tighten to 13 lbs-ft. Then slide on the locking tab, install the second ring and tighten to 250 lbs-ft., then bend the locking tab over one of the slots. Does this sound right for a 1977 3/4 ton?

Apologies for the lengthy post.

Joe F.