The more I find out the less I know. Pistol serial #C21182 S.S. made in Seattle
and stamped "detonics 45" on the slide. I have pictures that show the finish are lack of finish looks like a cast that wasn't polished.It has the arched spring housing which is in the parts drawings but the only one i have ever seen. If you can shed any light on this pistols model typr are anything about it please let me know if you would like to see the photos.