The concept of the "Alpha Series" was that special limited edition models would be produced and assigned a series (alpha, beta, charlie, delta etc) and sold with matching serial numbers as a collector's set. I believe the Alpha Series C2 & E2e were to come with an Eagle or back then SOE pouch specifically designed for them.
SureFire obviously decided not to limit the run to collector's sets as the camo jungle anodising was much sort after so they just released them individually as special edition products.
Perhaps the Beta Series would have been an E2e & M3 in a different camo finish - we'll likely never know...