I want get into a discussion on Glock vs. Sig here since I do not see this as the essence of your question. I see nothing in the Blue Book of Gun Values as indicating any major price differential between the "Special Edition Pistol" and the other versions. (The Navy is listed as a Special Edition.)
I personally doubt you will see any tremendous price rise of this model as a collectible in the future. It might be of slight more interest to select buyers particularly if they served in the Navy. Just my opinion.