Not many single throw switching devices are marked line and load anymore.
Fused disconnects have to de-energize the fuses, that eliminates any options with those.
Most breakers can be used any direction,
I got that info from an inspector on a job where I had to back-feed a main circuit breaker.
I agree it is a good idea bit the inspector was asking for something that is not required by the NEC
Or, maybe the last vestages of any wording that may have implied it are in 404.6(A-C)
"Single-throw knife switches shall be placed so that gravity will not tend to close them." And, by design... it ended up that way - 'Line on top'.
Once you get to double throw (a manual ATS for example) that goes out the window.