Hi Dalet and welcome to the forum.
You can learn quite a bit from our reference FAQ pdf. Download it from:
http://forum.lugerforum.com/showthread.php?t=13121
Replacement hold open springs are available. They are small and thin, but with care you can replace it yourself. I am sure LugerDoc has them in stock.
Post some pictures when you can, we can be of more help after getting a good look at your pistol.
And don't store it inside the holster. Keep them separate.
In addition to "6345" there should be a suffix letter under the numeric digits on the front of the frame above the trigger guard. That suffix letter is part of the serial number. The "8.82" is a bore measurement representing 9mm Luger caliber. S/42 was Mauser's military concealment code.
If it's all matching, realize that breaking a numbered part during shooting would reduce it's historic and financial value. That said, the Mauser made Lugers had excellent metallurgy and make good shooters.
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