Anything "Nismo" on eBay is probably not.
I also have Gorilla Nuts. Nothing special about them. I just like telling people I have Gorilla Nuts.
And Yes, WRX studs are a straight-fit. Nissan and Subaru used to have extensive parts sharing agreements, many of which continue to this day. the Subaru guys are all like "WTF?" when they find Nissan logos on the parts of their cars (example, the dial for the DCCD in the STi is the same part as the dimmer for most Nissan dash lights, and has the Nissan logo molded in on the back).