Your pistol can not be a genuine Simson if it bears a chamber date of 1940!
Simson's Lugers were all military guns ( very few commercials & even less with grip safety ) starting with WWI reworks ( dated 1917 or 1918 or blank chamber ). Dated Simsons range from 1925 to 1928 and last of the Simsons production pistols will have the S toggle. Some Simson Reworks of the Nazi Era exists but are mostly WWI dated guns.
Hope this small info helps a bit...
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