So you are the one who out bid me on that one!! I should have paid more attention!!
I can tell you a little about D&P Pipeworks.You can get more info here-- http://drgrabows.myfreeforum.org/index.php?sid=b27327dc51fa201c9aafbc7e32460cee
D&P was located in Sparta,NC. the present home of IP&A-the folks who now make Dr. Grabow pipes. They started out there during the WW2 era(or maybe just before. They went there because of the Rhododendron and Mountain Laurel grows there and they used it to make pipes since briar was hard to get during the war. At some point they were bought out by HLT,who had also bought out Linkmans and moved DG production to Sparta.
Several pipe companies used alternative woods during WW2. Kaywoodie had their "Mission Briar" line made from Manzanita which is the American version of briar,HLT may have used both Rhododedron and Mountain Laurel. The guys over at the DGCF can tell you more.