Gently push the speaker cone in and out, if you can feel any scraping (push evenly both sides) then the sub is toast. If it's wasted, you can get another 10" really cheap (ebay). If not, it'll work and that amp will power a small sub just fine. I have a 10" 125 watt sub in a good sealed enclosure and it sounds great. If you've got a decent .75 to 1.2 ft/sq enclosure you're good 2 go. Make sure you set the amp crossover to 120hz or less, if the amp doesn't have one, use an external crossover inline with the rca's before the amp, also cheap. Don't run it without some kind of crossover blocking highs to the sub, it won't hurt it but it will sound like poopie.
You don't need class D to power a sub, that amp is fo sho class a/b anyway. From your posts, it sounds like you are just trying to put together a decent cheap system for the summer, that amp and a small sub is what you want.