I got this interesting retro watch in a lot and am looking to see if anyone knows about it. It works for a while, but stops so I wanted to clean and oil the movement but can not figure out how to open it. There is no way to remove the back, so assume it opens from the front. There appears to be a plug on the back, I'm assuming covering a screw to remove the stem. Not sure if the metal band on the front holds a trim or if I need to remove the crystal alone. Thought I'd ask before prying and ruining it.