No
Toro & JD are the only makers that I know of who actually make & distribute service manuals for all their products .
MTD put out a very limited amount , most for Cub branded products
The others just send dealer updates when something crops up, if you are lucky.
It is no trouble to blow $ 100,000 making a manual to the press ready stage
So that adds anything up to $ 100 per mower, depending upon how many are made and mower buyers are cheap skates so a no manual mower is already in front in the price war before they roll off the production line.
Add to that there really are no critical measurements that are not in the owners manual.
It is not like your truck where the brake pedal must have "x" mm of free play & steering must have "Y" inches of toe in and "Z" degrees of camber & castor