Need bumper ID - 1963? Valiant

I recently got a front bumper for my '65 Valiant but it does not quite fit. The bracket holes don't line up & the measurements aren't exactly the same as the bumpers on my '65. There is "7777" stamped on the inside of this bumper. Is this a 1963 ? I looked up photos of the '63 Valiants & it sure looks the same. I thought maybe you guys would be familiar with the # stamped on the bumper.

Next question: if it is a '63 can it be installed on a '65 with different brackets?

It's a gorgeous bumper & has just been rechromed. I really need to know exactly what year it is for before I do anything.

Thanks guys!