I noticed recently that many of the bridges had lost much of their fine gold or black infill on the lettering/numerals. I had assumed that this was due to age and repeated cleaning, etc. Well, it is due to cleaning, but the result of using an ultrasonic cleaner. Fine for the parts, but the ultrasonic action pops out the gilt, etc. so the bridges with these enhanced markings should not be tossed in the ultrasonic.
The Bunn 60 hr. I bid in is in a good but non-Bunn case with a monogram. Now I will try to find a Bunn case on a non-runner/damaged movement.
The railroads, as you said, put some requirements on cases. At one time the 'swing' mounting was recommended. Plain silveroid/brass/silver/gold cases were OK, but no Hunter cases. Of course lever set was demanded, so the crystal and its mount had to be removable.
The railroader could buy his watch from the union, the RR, or from a catalogue or watch dealer. Businessmen who wanted a good watch could buy the same models. As olddude said, the case was often sold separately on older RR approved watch movements, the quality of case depended on what the pocketbook would permit.
Around 1900, a 'silveroid case', good nickel steel, cost as much as 14k gold, and was much preferable for hard use.