My GTRV van was built by Roy in the Richmond, BC, facility in 2009. Sometime after that, his son, Brian, took over the Canada operations, then the area where the shop was located was rezoned for condos and they moved out to Chilliwack, BC in the Fraser Valley, and then they went out of business. (Those latter two points are second hand, so I don't know the exact details.)
Mike Reed has been involved with GTRV for at least the past 15 (?) years, and was their sales rep in the States (while everything was manufactured in Richmond). In the last 6 or 7 years, he opened a second GTRV facility in Sebastopol, CA. I suspect that this took work away from the Canadian facility and led to its demise.
Anyway, I was recently (Aug 2016) in touch with Mike Reed, and purchased a new bulb seal for my T-Top on my Ford E350. It arrived promptly, although I haven't installed it yet. No concerns about being an Econoline.
If you are looking for the T-molding for your interior, as arctictraveller mentioned, it should be available anywhere. Try your local buidling supply or home centre, or the interwebs.
2008 E350 EB, V10, GTRV Conversion