They most certainly would be prototypical. I'm also interested in early covered hoppers because they come in a fascinating variety of stylesunlike hte later 1958 cuft cars and later PS cars which all looked the same. I have collected a small file of photos at work of B&O, NYC, PRR and other early covered hoppers and I'd be happy to share the photos with you. E-mail me offline at Golden1014 at Yahoo.com.
I just ran across a photo of a NKP car, rebuilt from a USRA hopper, that I'm dying to model next in HO. RCW makes decals so it should be easy using a Tichy car to start with. I recently finished kitbashing an HO model of a C&O car (300-series) which was easy to rebuild using the Intermountain car.
I'm sure these cars generally saw captive service on their home railroads but we could justify one showing up from time to time.