its a 1940 (year) 42 (Mauser), a hundred + thousand were made.
NO valuation can be made without knowing more? I assume this is the all matching. Does this include all small parts and internals (they should have the last two of the serial number.
See the FAQ for some info on these and what should be marked.
Do a search of 1942 40
Do a search on gunbroker and see what like items have SOLD for
Do a search at Simpson's LTD but deduct 40% off since they are a high end, but with good reputation company, and being retail more expensive.
Tom Whiteman has a couple of lugers on 'June" sale right now at
www.legacy-collectables.com
Ed