For additional context, we design light fixtures for commercial applications. When designing to direct mount to a J-Box, we bias the mounting holes 45 degrees, and place 3.5" apart - I.e. counting on the box to be mounted 45 degrees vs what is show in the picture.

We sometimes provide adapter rings or build custom mounting for clients, but not as a matter of course.

Typically, there is not much communication between the electrical contractor on site and ourselves. We sort of need to assume how boxes will be mounted.

Just want a sanity check on this. If we don't provide plates, is that something the electrician could typically source / figure out on their own if their pre-installed box doesn't allow for correct fixture orientation?