Side View Mirror

Hi,
I was checking the mirrors on my 59 SKyliner. From first glance they appear to be the standard round mirror mounted on the fender. When I look closer I think the base of the mirror is a little longer and narrower than what normally appears on a 1959 Skyliner.

When looking at other cars it looks like the hooded mirror has a fatter and narrower base. I measured it at approximately 5.75 inches from end to end and 4.75 inches to the screws.

The measurments of my mirror are 7.5 inches end to end and 5.5 inches from screw hole to screw hole.

Does anyone know what year my mirror is for if I wanted to replace it?

I would put the shorter one on but the longer mirrors have been on for at least 10 years so there is some cosmetic touch up that would need to be done if I went shorter.

Thanks for the time