The Cat SNID book says they started production in 1967 so as low a SN as it has I,m guessing it came out that year yet or 1968. A book I have says they had 93 HP but I don,t have the weight of it as it wasn,t listed in this Classis Caterpillar book I have by Keith Haddock & Eric Orlemann.
The info I have shows only one year of production (1967).
Basic weight is 18,600 lbs.
D333 engine at 93hp.
The manuals for such a limited production might be a little hard to find or combined in one of the many similar model service books.
You could try here under "track tractors" (doesn't seem to be working this am😕 )
http://www.cat.com/cda/layout?m=90800&x=7