Hi Richard,
I would suggest you switch to Jan Still's Gun Board and read through the following posting :
http://luger.gunboards.com/topic.asp?TOPIC_ID=6491
Here is a continuation of that discuss in aother thread :
http://luger.gunboards.com/topic.asp?TOPIC_ID=6489
If you can meet with this dealer and make arrangements to take detailed photos and post them on the Forum, I am sure folks will help with their opinions and info.
Given the fact that it is rumored that many pre-production Swiss lugers were forged/boosted in the 1990's, one should proceed with caution and have local advanced collectors (not associated with the sale) to assist you.
LF member Ron Wood lives on the border of TX and NM...he might be one fellow close enough to help you beyond the help you might receive on the Forum or on the Gun Board...