I dont know which thread this was in but a member on here has a Bolens 800 188-01 with an extra 7 stamped into the model.
There was some speculation on what this may mean but I came across an older post from another site and this is what it says:
HOWEVER, there was a Bolens Letter issued to dealers explaining that some 800's were shipped from the factory with an S7D in place of the S8D.
I don't remember the reason why - possibly a shortage of S8D's. ...These tractors were identified with a "-7" suffix added after the tractor model number.
Also, Bolens production did not always match what was shown in the brochures. ...Even production info published by Bolens has numerous errors.
I, too, worked in a Bolens dealership while these tractors were being sold new. ...I do not recall ever seeing a 1964 or 1965 Bolens 800 with the S7D installed at the factory. ....That is not to say that a different dealership (or distributor)could not have received a batch of the 800's equipped with the S7D.
I have to say this does seem to be legitimate as the tractor in question is indeed equipped with the S7D Wisconsin engine!