It should scrape off with some moderate-to-vigorous effort. The canvass is glued on. For scraping off, make a jig to hold the slat steady. Scrape with a sharp blade.
You can try a hair dryer on high heat or a heat gun on hot. Don't burn the wood. The heat should soften the glue enough to peel/scrape off somewhat easier than scraping dry glue.
When re-doing the slats on new canvass, set up another jig to accommodate the placement of the slats in their "door" position, with the glue side facing up. Note in the video below, keep your tambours square to the end pieces. Paint some glue over the slats and lay the new canvass on top. Personally, I'd put just enough glue to coat the surfaces.... no excess. No excess means no glue clean up afterwards, i.e., cleaning dried glue is somewhat labor intensive and good bit of time cleaning up in all those little curves and crevices.
Here's a pretty good video.https://www.youtube.com/watch?v=o9auSpBZl_k