Ours is original to us, but far from original in build
Also I made a typo up there, I think ours is a '47 not a '37...I'm pretty sure the A series wasn't started until 1939. It's hard to tell now though due to the age and number of rebuilds it's been through.
My grandfather purchased it new, but in 1982 it was severely damaged in a barn fire and rebuilt the following year from the ground up. Several things aren't original to the tractor, but were added in later years models like field lights, an alternator (as opposed to the original generator), and a battery starter. I don't know how much of the tractor is even original