parts availbility for CAT 140 grader yer 1971

Notice local govt accepting bids for a 1971 CAT 140 motor grader, I am wondering if its to old to purchase.
My concern is the replacement of parts, CAT does not stock.
It's in decent shape has been used continously, they upgraded is a newer CAT 120G.

parts availbility for CAT 140 grader yer 1971