Seems mad if it's not designed to be serviced! Why use bolts if they're going to glue it permanently? My guess is hot glue, but whatever they've used must have dried to a brittle state by now. It'd be easy to scratch, bend or otherwise permanently damage the fascia using brute force. If those were my speakers, I'd lay them flat face up, then gently but thoroughly heat just that area using an electric blanket for several hours (shouldn't get hotter than 60 degrees C) , then tap it lightly all over the edges with a rubber mallet (cover the fascia with a thick cloth to protect it from the rubber mallet) to loosen things up a little, then try again to pry it apart using plastic prys only. If that didn't work, I'd heat again using the electric blanklet, plus use a hot air gun afterwards, risking damage - using a very low setting (start with 100 degrees C), over one corner to start with.