You can´t, could be literally anything under the cover. Even if the cover said SD it could still be a Gibson, Dimarghzio, Fraliln, Holmes, or about 1000 other things underneath it
There are only 4 screws if it´s a Humbucker in a ring, all ya gotta do is loosen teh strings. What does the Baseplate say, and if it´s a duncan, the STICKER on the Baseplate say?