i believe so , or very closely related. if it aint broke dont try to fix it comes to mind! plus moulds would have been on the shelf, as these were to try and compete with the foreign imports at the time, and the likes of merry tiller and danarm that were about in the late sixties and early seventies. the 55 was later altered so it didn’t have a bonnet and side casing, and just had a pully and belt guard, to cut costs further.