I don't recall the thickness on my 1991, but they do have to be pre-bent. There is too much bend to just hope the 795 seals them.....the screws on the side windows, if there is actually a screw in the hole, is just to hold the unit in place until the Dow 795 sets up. It takes a while to do so, I waited a week and was still careful with them, as the specs say 30 days for full affect.
Then you take screws out, seal that hole with a dot of Dow.
I would talk to hunter/marlow and see what they may have ? The cutting is precise and would have to be accounted for in the bend, to work properly, or you may end up shallow in spots, that would likely leak or present problems down the road. Make sure the shop does not use conventional silicone lube or materials as the DOW does not play well with it.
There is also the material selection, do your homework or again ask hunter what they used. Acrylic, lexan, poly, etc. I don't recall - but some materials will never seal with the DOW and some materials are prone to clouding/streaking/breaking down. Don't let the shop talk you in to the wrong stuff.
Back in 2009, I found a place that had 4 of the side windows in stock, again ask hunter for a list of their suppliers or contact Phil here, as he may know someone who has NOS units or can fab them. Would be worth a few phone calls.