The Twin Falls Daily News on May 21, 1937 said that a $40,000 fire destroyed the old Wheaton Theatre in Weiser earlier in the day. The Bend Oregon Daily Bulletin said in their coverage that the theatre was worth $75,000. At the time of the fire the theater, built in 1908, was once the premiere center of entertainment but had been closed for many years. 
The Wheaton Theatre is listed in the 1914 edition of Julius Cahn’s guide as a second-floor house with 567 seats. The 1906 guide had listed it with 850 seats. All of the available Cahn guides I’ve seen in which the house is listed call it the Wheaton Theatre, never the Wheaton Opera House.