A long time ago, I had the pleasure of playing one of these Allen TC-4s for several years in one of my many organist/choirmaster jobs. It was extremely well-built and very solid. The stops are equipped with SAMs and there is a starboard in drawers under the side jambs. The sounds were very good for the time - but rather limited. As I recall, it has three basic tones plus the Allen "rank change" controls like "flute becomes stopped, reed becomes one, and celeste strings."
This is definitely one of their AGO consoles with good keyboards.
Assuming it all still works, this would be a great starting point for a HW project.
Les