I followed the link but all I was able to find was a long list of every single seminar they are holding anywhere. After working my way through to page five (or was it six) on my slow connection, nothing matching your description was listed for Jan 31. They are holding a ton of events at the centennial gun club that day, and simultaneously at the Tanner gun show, but no event in Castle Rock that day.
Maybe I'm blind. [Doggone front sight disappears against a black background and limits me to three inch groups at five yards. Still within minute-of-bad-guy.] If so, I'll still suggest a more direct link would be useful.
[add--well I got past the fifth-page issue by actually following Step One, which I didn't spot the first time even though it's not black on black. But still, no event listed in Castle Rock.]