Yes the 405 and 405A are made to fit the Tube frame Bolens tractors.
Neighbor just got his 405A rebuilt.Every bushing on it was worn out.He paid WAY to much for it considering it's overall condition but it was complete and had a fairly new set of knives on it.
He got it back together the other day and ran it for a bit but it's pretty quiet running now.It chattered really bad before and kept tossing belts.The main bar pivot bushings were worn so bad it was making the belts pop.He paid $450 for it and had another $150 in it in parts and labor.
Long story short.Look it over really good to make sure it's not worn out before handing over any money.
PS O.B. My neighbor Matt said thank you for the manuals.He could not have got it back together without them.