Not that I know of for a certainty. I’m sure both of ‘em have lurked from time to time. I’m pretty certain Corsi posted at least back in the 1998-2000 era. I’ve never seen Rush post, but have heard him take the same point of view expressed here from time to time.
I think i corresponed with WF Buckley here on FR. Of course Limbaugh monitors this site. Its probably where he found the thread of “Post your Kerry Girlyman Pictures here” that i ran. It had something like 30,000 hits and some of the funniest posts i’ve ever seen.