Lets play...guess the gasket!

If 6 is the same size as 7 (it's hard to tell scale here) it could also be an oil filter o-ring. Felpro 70078
https://www.summitracing.com/int/parts/fel-70078/overview/

When I was putting my headers on and ordering gaskets for my 90* adapter. I came up with two numbers. Felpro 70522 (your number 7) and the Felpro 70078. I ordered both just incase, they weren't expensive. I ended up using the 70522 (paper style gasket) and not the o-ring. Not sure if the o-ring would work. But if I recall it was listed as correct for some models/years.

The kit probably gave you both to make sure you got whichever one you ended up needing.