Dear John D.
Since you are in my neck of the woods, I figured I would throw in my two bits. Just remember, "A LITTLE BIT OF KNOWLEDGE CAN BE DANGEROUS WHEN IT COMES TO COLLECTING LUGERS?"
May I suggest that you attend the West Springfield Gun Show at the Big E on December 11&12 2004 and Albany Gun Show at The Egg on January 22&23 2004. At the West Springfield show there is always two large Luger dealers, Anderson & Walsh are the guys last names. Both have a good supply of Lugers. However cost is right up there.
My suggestion would be as everyone else has mentioned, spend the money and buy Jan Still's books a few others. Then keep an eye in he wantadds and maybe enter an add in your local for sale digest under guns that you collect Lugers.
By buying from the owner, you sometimes will get a pistol that has not been messed with. Much of the time price will be very attractive as these guns have been in the same family for many years. Also there is no sales tax, I reside in New York.
See my listing on this board below. Found this GEM in the local for sale digest and is all original with matching grips, 1915 DWM and cost was $600.00 cash!
The only other suggestion I can make is before you buy any Luger, view it under direct sun light, outside! The sun seems to bring out everything. Inside under florescent lighting, stuff always looks great. Many years ago I purchased what I thought was a mint 1941 Byf Luger from a small little gun shop who the owner said he had owned this Luger for more than 20 years, who knows for sure. Paid much money for it. When I took it to the range I was shocked at the finish. It had been touched up in many areas. I did not get hurt financially as I sold it off at a gun show to a dealer a short time later and broke even.
The best of luck and let us know how you make out in your Luger Search.