Having just seen a similar thread regarding another W.O. Larsen Straight Grain, I thought that for posterity I should update this one to share that Rob Cooper told me that he was certain that my pipe was made by Benni Jorgensen.
I could see that. Almost all of my Larsens are from the earlier periods Rob mentions in the quote above. A lot of Sven Knudsen shapes. "Very early 1960's to the early 1970's", and "Mid 1970's to the mid to late 1980's"
Just two of my older Larsen's,
http://pipesmagazine.com/forums/topic/larsen-copenhagen-special
http://pipesmagazine.com/forums/topic/larsen-handicraft-de-luxe
If I had to guess, I'd say I have 50 or so Larsen pipes.