You've been listing 7 downtown casinos that Jackie Gaughan owned part/all of, that will be included in the MOGH display:

Boulder Club
El Cortez
Gold Spike
Golden Nugget
Las Vegas Club
Plaza
Western

After Jim Follis found evidence in his coupon books that Jackie also owned the Nevada Hotel at some point, I started searching around more.

Found this on LAS VEGAS (KSNV MyNews3.com) website:

Beginning with the old Boulder Club, he owned and/or operated 11 more casinos in the downtown area – the Pioneer Club, Las Vegas Club, Golden Nugget, Showboat, Union Plaza, Sundance, Nevada Hotel, Club Bingo, Gold Spike, Western Bingo and his beloved El Cortez.[/blue]

In addition to the Nevada Hotel, I think that Club Bingo needs to be added to the list. KSNV mentions the Pioneer Club...so did an article in the Las Vegas Sun. This is the first mention I've seen of the Sundance.