wench-bumper question

I have been looking at the Viper wench and mount kit and it says if I have a heavy duty bumper it might need to be modified. I got the atv used and it had the bumper on it already. I will take it off and sell it before I start grinding on it if its a major fix. It looks nice but for how I would use the atv I probably don’t need it anyway. Have any of you guys had to grind your bumpers and how much grinding is involved with a heavy duty bumper ? Would the Warn fit without the grinding process ? Thanks