Nope. You've misunderstood the entire system. Why do you think there are two Mks per tier? The lower Mk (odd Mks) has always been the cheap, vendor-available, moderate gear and the higher Mk (even Mks) have always been the drop-only or badge/mark/emblem-vendor-only gear. Both Mks per tier then also have a rarity - White/common is moderate, everything else is not.
Uh, no. White Mk 2, 4, 6, 8, and 10 ground weapons always used to be in the weapons vendor on earth. I recall seeing some other even mark whites in vendors for EC, though not specifically which ones or where.