Here is an illustration of the non-glare mirror and bracket.
page 21 of the 1954 Truck Data Book (Oct 29 edition) - TRUCK ACCESSORIES - Mirror Bracket, Inside 1947-55 (All models)
It looks like the mirror bracket could be ordered separately from the non-glare mirror. The 1954 interior mirror-bracket being a different arm and a different non-glare mirror from the none glare mirrors used 47-50, and 53 (shown in the MPB). I do not know about 51-52 - they are not shown in the MPB, but a non-glare mirror is shown in the 1951 Truck Data Book.
I can't find any "standard" interior mirror listed in the Master Parts Book (or Truck Data Books) for 47-54.
Does that mean that I have to put a non-glare mirror inside my trucks, if I want to be "correct"?
Regarding the installation of the 54/55 interior mirror arm, here is an earlier post with some photos