There is some evidence to indicate Lugers appreciate faster than inflation and therefore could be considered to have investment characteristics. Provided that you didn't over-pay.
http://forum.lugerforum.com/showthre...ight=inflation
But the are caveats. Absolute dollar value or everyday utility IMO do impact collectibles at times. I wouldn't want to sell say a Rembrandt or Borchardt pistol at the hight of a recession or other tough time due to the possible scarcity of buyers. So I'd consider Lugers illiquid from an investment strategy standpoint.