Yes 10-32 and you can find or make knurled nuts (for use just with your fingers) that make life easier. Getting a socket in there isn't a lot of fun and they do not need to be over-tight.
In fact some of the aluminum ones that come with aftermarket gauges are the right thread already (or if 8-32 you can drill and tap a size up to 10-32). Otherwise I've made them on the lathe, but that's not for everyone.
