A TV ad-buying company with close ties to Republican Party leaders reserved a whopping 1,326 spots in the Denver market this fall, but the station receiving the $740,070 contract removed it from public view when a reporter tried to learn who was footing the bill. The deleted ad reservation at Denver’s KMGH Channel 7 came from Target Enterprises, a Los Angeles-based firm whose client list includes top Republican candidates and well-known conservative groups.