Restoring an Old Town Dinghy - Question about Canvas


I am restoring an Old Town Dinghy from the 30s. I have removed all the canvas and there is a lot of canvas "remains". Not sure what to call it but it did not all come off cleanly. Do I need to scrape off all of this residue (wood filler?) and remaining canvas that seems to adhere to the cedar? Or can this be canvased over when I recanvas? See image.

It looks to me that your dinghy was fiberglassed at one point, and what you are seeing is some residual resin. If it is bonded tightly and has been sanded smooth, you can probably leave it without ill effect. Otherwise, carefully heat it with a heat gun and scrape it off.
I'd use a heat gun to soften it and scrape it off. I would not sand until it is off of the hull. Sandpaper will attack the resin and soft cedar at different rates and you'll end up gouging the planking. Canvas will hide a multitude of sins, but why chance it.....
So if this was possibly fiberglass at one point (please excuse my ignorance), would the fiberglass come off like hard plastic? As I pulled and scraped off the old canvas, ther was a lot of cracking and breaking of what seemed like a hard plastic over it. Or was this possibly orignal canvas, then fiberglassed, then recanvassed? Thanks and again, please excuse the ignorance ... first time restoring a boat.
Could have been fiberglass - look at it closely to tell. Canvas stays flexible and isn't bonded to the hull in any way. Polyester resin (which was commonly used) does not adhere to cedar all that well, so sometimes when you get lucky, you can just pop it off without too much trouble - sounds like you got lucky! Since the resin is on the planking, the original canvas was removed prior to canvassing.