David,the guys seem to have all the bases covered,the main complaint I hear about AD trucks is the front windshield seal,it's unlikely you'll need any sealant in the rear cab glass.
The main problem seems to be getting accurately cut glass. The seal requires the glass size to be correct to 'push' it out to correspond with the aperature.
I can't vouch for Jim Carters glass but like the guys have already mentioned I would fit the glass 'dry' and then water test it,you'll soon find out if it needs any additional help!
Most likely offenders will be the lower windshield radii.
As 64fleetside already mentions 3M do a non setting glazing sealant specifically for this purpose and while it doesn't exactly flow,you can apply it once the glass is in should it be required and unlike some silicon products,wont hurt your paint
