I realize Governmental plans are not subject to minimum funding rules and the timing requirements. However, I can not find anything that indicates when Gov't organizations are required to make a contribution to a 401(a) plan. I have always understood it to be within 12 months following the plan year. Any thoughts and sites that would support the timing requirement?

Most likely, the due date (if any) is governed by state law (or possibly local law).

Yes, inmost of the cases the due date would be called as that decided by the State. If like to have a further opinion about this I would suggest you to contact an attorney in your state as he would be able to suggest you in a better way. As the matter and the due dates are decided pertaining to the State laws the information gained would be of good use to you.