Lugar information needed

I would appreciate information about a Lugar I have recently acquired. It is in excellent, mint condition. Above the trigger I noticed three "X's" with crowns above them. Next to these is an eagle with wings spread. All the numbers match on the pistol. The numbers are: 70185. At the top of the pistol there is a monogram that says "DWM." The handle appears to be walnut. The pistol is not dated, but I have been told that it is possibly from the year 1917. The leather holster is a mahogany in color and is worn. I would like to know the history of the pistol, how to care for it, and if I can shoot it. I would appreciate your feedback.

Thank you.

Joe May