P.J. -
This is the right site if you want to know the factory numbers and markings on L's aircraft or how many planes he shot down and when, but for your question I would go to these sites:
http://www.wehrmacht-awards.com/forums/index.php
http://gmic.co.uk/
Each has sub-forums for uniform pieces and expert collectors there who can price them for you. Both sites are wholly devoted to the collector of these items.
Larry