Wings are bought separately. You could have an odd number of wings, but you get bonuses for having a pair of wings within 2 size classes of your torso.
Servos generally can be as tiny as you want, but Leg servos have some restrictions (p.20) and you don't get the +2 MA bonus if your Wing servos are too small.
I'm going to inject an opinion here, as a former mecha RPG player. The Mekton Technical system (across multiple editions) is a complex mess. It's RPG Sudoku; you'll spend a lot of time doing a lot of math for very little benefit. The system used in Heavy Gear/Jovian Chronicles, where you just pick your mech's final stats and plug those into a formula that tells you how expensive the mech is, shortcuts a lot of the tedium. On the other hand, the attendant combat system is simpler, so YMMV.