It is the contract year, not a production date year. By the way, the FY used to run July to July; they changed that in the late 70's because they had difficulty getting the budget done, so they took an extra 3 months and now sometimes don't ever get it done at all (e.g., Obama Admin).
By the way, usually production funds are multi-year and do not expire until 2 or 3 years after the end of the FY. O&M funds expire at the end of the FY. This probably was still true back then.
I used to work at the Pentagon.