Loren, you as well as a few others on here could answer this, John, Tom, Melvin, et al.
I have seen the square nose design on tractors called a 350 in the past on eBay and other sites. Were there some 350s made with the 500b/600b sheet metal or were these tractors misnamed in the ads? If so how many and the 350 was made in row crop/general purpose only right?
As well my 630 Section A service manual says to use the 500b/600b/350 services manual until all sections of the 630 series manuals had been produced so that lead me to believe there were a few square nose 350s around.