I decided to tackle the rust, bodywork, and paint on my 1926 coupe as a labor of love.
I'm unearthing various previous issues, like large dents filled with way too much Bondo, etc. To be expected, for sure.
Both driver and passenger A pillars have some holes in them (I assume for mirrors). I don't believe they are Ford original, so I am considering welding them closed.
Are there supposed to be holes for external mirrors on a 26 coupe?
No, any external mirrors were an aftermarket accessory. All enclosed cars came with the interior header mounted mirror. Replacements were available from the dealer for 75 cents or $1.25, depending on which source you believe.
If you don't have mirrors I would suggest using the holes and mount some. If you drive the car they are a good safety item along with brake lights and turn signals.
Hinge pin mounted mirrors are a better bet. No holes. Mounts in the existing door hinge pin.