Alan,
Will your 54/55 seal/windshield have the stainless-steel trim? If it does, take a look at the "dry fit" of your glass in your cab opening. If your glass (especially if it is a reproduction piece) is a tight fit, you might have difficulty getting a good fit all the way around. Most likely even a professional installer would have a problem doing this installation. I would not go to an installer who has never done this specific installation - they'll say they can do it but they might end up having problems you will end up paying-for.
If you have no stainless trim you will most likely have no problems installing the glass yourself (use a sealant as described in the 1954 Shop Manual).
