I contacted Forum and they said there is a 3 degree bevel on the Destroyer and on all of Forum's park/jib boards.
That's a pretty intense bevel. I am quite surprised. My geuss is they also have a 87 degree side bevel. So you can either leave the edges alone to maintain the 90 degree corner, or buy a 88 or 90 degree side sharpener and round off the edges slightly for a more forgiving edge.
I'm quite surprised ... when I checked the board I didn't see any bevel, I guess 3 degrees is just hard to notice.
Anyway, would this mean I don't have to take a file to my board to avoid hanging on rails ?