After a collaboration...it is determined that the MEC chips were sent to George Perry of Reno, NV. 1939 (Not Miles E. Custer) It looks as if George Perry rented a spot inside the State Line Country Club near the Main Entrance of the building. Thus calling his business "Main Entrance". The Main Entrance sign is believed to be the main entrance of the State Line Country Club and not a separate entity. So.... this chip is still attributed to The State Line Country Club since Perry was believed to be renting a gaming spot inside. We will continue to search for more answers.
When categorizing this chip I am going to say (For my personal records).....

MEC
George "Frenchy" Perry (Reno)
Main Entrance/State Line Country Club
Stateline, Nv 1939