Hey Sean,
Yes both your 18s started life as Model 5 series 1s. The second mower looks closest to being accurate in regards to its overall cond, and In my opinion the best one of all your previous 18s, and would benefit from a full resto to original for your private collection:) So dont go painting it pink! Lols
The starter on the first appears to be off an Auto more so than a model 5S2, (and yes its on backwards). Std wire cord with split half alloy pull knob.
The twin pawl recoil starter engages to the dognut instead of a cup like the later cord recoils.
Pawls and carrier fail often on these and parts are like gold. I also find the cord std recoil starter much smoother than this one. If its got broken bits just swap it with a rope start or std recoil.
The knob is held together by a rubber boot that hilds the 2 halves together. Remove it and you can split the halves, keeping in mind you wont be able to reuse it judging by its cond. And No you cant buy a new one! Neatly tape the halves then finish it of with a few layers of heat shrink if your gonna use it