The Scottish Rite Masonic Temple was pretty cool.
https://guthriescottishrite.org/
It was built in 1921 and cost 3 million. They said it would cost over 700 million to replace it now. Very neat place. They picked Guthrie because it was going to be the state capitol and they wanted to be in the center of it all. The City of Guthrie built a community hall and used it for city offices for two years, then the state legislature actually met twice there. Then the great seal was taken to Oklahoma City, and the legislators all moved to OKC.
They eventually put a connecting hall to the convention center and it is open to weddings, and parties and even has a full kitchen downstairs that can handle 300 people at once.
One cool piece of history they do have is the feather or Quill pen Teddy Roosevelt used to sign the statehood proclamation. It was said that the feather came from an Eagle in Oklahoma.