Not sure there is much I can help you with
as you are on and correct
pre-WW1 made Luger that went into army service in 1911
It has an interesting rc eagle - which is an acceptance by a supervisor at the factory once it was turned down (see FAQ)
post war it came to America - could be a bring back, it could be a import - as many were marked germany or made in germany when made new or refurbished by DWM, but lots of lugers were imported without being export marked or import marked prior to 1968
The sear could be a replacement by an armorer or by whomever put on other missing or mixed up parts, or it could be that at one time in the mid 1920's (1925+) to about 1934 when Simson was the official manufacturer and refurbisher for the army.
Ed