I know a lot of commercial panels I have sold when I worked at the supplier HAD doors, and most of the resi-panels you could order a door kit if you required them.. They are still allowed to be " doorless" as far as I know, and FPE is the only one off the top of my head that has no doors on their residental panels, but has a door kit option availible...
That panel in the picture, was it a "used" panel???? I have only seen FPE panels with that colour enclosure, and that "old style" main breaker (150 - 200A I believe) manufactured in the early to mid 80's... The " black and white" breakers I think came out in the 80's as well, versus the earlier ones like whats in the bottom right corner, that are black handle, black body....
A.D
