If it is within the boundries of the gun show then it falls under the BG gun show check. Now if you decide to meet prior to a show on land the show does not reign over then it is a private/FTF sale.
A gun show is defined as 3 or more people meeting to buy, sell or trade firearms anywhere in the state of CO.
When you go to tanner off 58th you will see a sign entering the parking lot just past the fast food lot stating this is a gunshow, or something like it.