Congratulations on finding one so nearly complete - I have 2001 and 2120 - both less cab and in sad shape. I'm assuming you already know there were 3 versions of this tractor - actually 4 in practice.
s/n 1001-1038 were Navy
s/n 2001-2243 were USAF with PTO
s/n 3001-3427 were USAF without PTO
And there were US Army Corps of Engineers versions which appear to come from the 3000 series which may not have had cabs
Post some pictures including the tags or you are welcome to email me off list.