Steve, Nice looking boat.
I think that back in the day if the builders had epoxy and cloth at their disposal the canvas covers would have disappeared overnight. The early attempts at cloth and polyester resin lasted about the same as a poorly done canvas job so canvas remained. I would bet a dollar to a doughnut (What does a doughnut cost these days?) that what Craig is referring to is a polyester resin and cloth scenario.
I redid both the canvased forward and stern decks of an old 40' motor lifeboat with cloth and epoxy. I replaced the cold molded planking and deck beams where needed and then sheathed it. It turned out like it should have, still has the canvas look to it. That boat is 40 -50 yrs old. So far it is holding back the elements like it was done yesterday. Not boathouse kept. Around here canvas covered wheel houses are a thing of the past. Some are still glassed with polyester resin but we use two layers of chopped strand matt with no cloth. That thing with cloth and polyester resin does not stand up. Epoxy and cloth does work though. Most of them are plywood with wood caps. Cloth and epoxy or CSM and polyester resin covers the whole works. They are all work boats so they get their fair share of abuse from the elements and or wear from storing stuff on them. Both of these methods allow us to seal the fasteners that hold down the deck hardware, antennas, radar masts etc with the 5200's, Sikaflexes etc. and stop the problems that arise from water intrusion.
Now after having said that I would be inclined to keep that boat original in construction, ( thinking like that is a curse for sure) but I just can't go up to the CO-OP store and buy canvas any more though so I would have to research my options there. It has been 15 yrs or so since they carried it, but this board should have an answer for that.
Watch when you take it apart for signs of where the problem areas started (if there are any. Why are you taking it apart?), nail sick where the canvas was tacked, deck hardware,damage from impacts, and scratches etc. Let the boat do the talking.
Take a bit of time and enjoy it.
Neat old boat for sure.
Eric