The code Gawds may raise hell with this suggestion, but if you want to go for appearance using the original screws, JD weld the hole closed then re - drill and tap.My house has three Siemens panels. Two @ 200 amp and one @ 100 amp generator panel. All three panels have at least one stripped panel cover screw. Any suggestions?
If this is a machine screw a nut may work if it could be JB welded to the inside using the screw for alignment and holding the nut in position until the epoxy or JB weld dries. Or a thinner piece of metal pre drilled and tapped used in the same manner. May want to apply a small amount of release agent to the screw.The metal is so thin, i really don't think it will work.
All the Siemans panel on 200 amp size they typically come in 6 screws ( under 42 spaces ) while the 100 amp size panel typically only come with 4 screws.The poster was asking about the screws which hold the panel doors on. To say that the Siemens panel's door screws are "unique" would be a mis-statement, they are indeed weird. IF memory (?) serves me correctly the 200 and the 100 amp panels have six (6) screws which hold the door/cover on. IF only one screw is not tightening properly I believe that this is still within code--check local coding on this. I'm not sure about placing anything within these panels which could come loose, may be an NEC violation.