Intake manifold is it stock..which gaskets to use

I'm not claiming I've done 50 manifolds and never ever had a leak, but I pretty much don't do anything previous poster does other than drilling the hole in the thermostat.
I don't understand what the "left front corner (passenger side)" even means.
And I don't understand the fascination with those Chinese chrome thermostat housings. It seems I'm always reading about them not sealing properly. Myself, I just get a cast iron one from NAPA, and paint it to match the engine. They are more rigid, flatter, and don't distort like the aluminum ones. I'll live with the extra 5 ounces of weight.