Is this for a 8"

The seller is obviously confused. "Not a posi" well that goes with out saying, posi is a GM term. "Just a limited slip" yea it limits slip to one wheel .

Why would anyone want an open rearend with 4.11 gears?

This is a good set of dana 4.10 gears ring and pinion

Click to expand...

Thats a give away, last I knew dana was a rear end.. dana 44, dana 60 etc..
Save the $76 and put them towards a new set of gear that you KNOW will fit..

It's hard to see a pattern on those gears, but what I can see they look decent. Throw a mini spool in there and go to town.

Most guys I know put gear marking compound on the teeth and run the gears by hand to show the pattern. The pattern should be centered on the tooth inside to out and not too deep and not too shallow.