Nate,
The bottom of the grip should follow the edge of the frame. It overhangs the frame edge so much that it partially covers the stock lug. It might be a repro. You can find grips on Ebay and other auction sites such as Gunbroker or Auction Arms. First you should try to contact Tom Heller (Lugerdoc). Hopefully he will read this and respond.
Here you go...
Gun Parts Sales & Repairs
Tom Heller (Luger Doc)
P O Box 398
St Charles MO 63302
Tel 636-447-3006
Email-
hellerarms@webtv.net