* "S" coded Simson.
* The "25" is the last 2 digits of the S/N (325) & not part of the Maker's Code.
* The small 33 on the top of the gun, if it is surmounted by a smaller eagle, is an Inspector's Acceptance Mark similar to the 4 shown in the receiver picture above. In fact, you should find an E/# on every Simson part of this Pre WWII example if the buffing wheel was kind. But, if the "33" is solitary, it may indicate a non matching, replacement part from another pistol.
* The pistol's history makes this of value to you & your kin. However collector's value has been decreased to that mentioned above by the nickle re-finish. I'd enjoy it for what it is, learn from its operation/markings as you are doing, have it checked by a gunsmith familiar with Lugers, and maybe shoot it occasionally on an anniversary (or whatever trips your trigger) if you dare. <img border="0" title="" alt="[Wink]" src="wink.gif" />
Respectfully,
Bob