Dont know who or when... a pic I found online...
I have a Sherman ARV Cupola with the spacer ring which will go onto my Firefly when it is restored.
Whilst not original to the vehicle, the original cupola "disappearing" somewhere between recovery from the firing range and my acquisition, clearly from the attached pic, Fireflies were fitted with them, so it will have to do.
I have some other pics, will dig them up and post.
I also have some documentation on this from National Archive, (edit) have now looked at that and unfortunately it does not reference the M4 Sherman, so wont post any extracts
Tim