A class I TA for uses Raspberry Pis for a project we assign the students. The various pis we hand out are a mix of model 3B and 3B+. We're running into an issue with some of them and think a potential reason might be that the OS image was originally deployed on a 3B and is now being used on a 3B+ or visa versa. The image deployed on all pis uses Raspbian GNU/Linux 10 (buster) as its base (archived 2019-09-26).
Is there a way that we could check to see what version pi the image was originally deployed on?
We know that you can check the what model the sd is currently operating on but don't know how we would check for information related to the original deploy. We are thinking the deploy process might leave some sort of marker based on the hardware differences between the 3B and 3B+ that we might be able to use, but we aren't really sure where we'd be able to find any such marker.