Almega,
I have a Logan model 815 which is obviously different than your lathe, but they are all similar. I don't believe there is a spring on that cast gear cover. The standard design has a spring loaded, threaded knob/handle. When you screw it in, it locks against that cast tab in your picture, which holds the cover closed. In your pic it looks like that spring loaded knob has been replaced with just a fixed knob/handle.
Do you have a manual for your lathe? It may show some detail of what I'm talking about. If not I can probably send you some pic's of mine. Making the parts would actually be a nice little project to make on your lathe.
Your magnets will work fine if you're not interested in having the original stuff.
Hope that helps.
Steve