Amp in Premium Sound

Sorry for the n00b question -

but, how do I tell if I have an amp in a 96 Explorer XLT with premium sound stamped on the back of the speakers. I have looked everywhere.

And, if I do will it hurt if I install aftermarket speakers to leave it plugged up?

Thanks!

you can use after market speakers but if you want to change the stereo you can still use the stock amp but wont sound so good. your gonna have to re-wire all of the speakers, meaning you got to run wire to all 4 speakers from the stereo or after market amplifier. you can tell on the harness on back of the stereo. theres usually a clip for the power and a clip for the speakers on the one for the power look to see if theres a blue wire, if it's there thats the remote wire to turn the stiock amp on and off if it not than you dont have premium sound. i wouldnt try to look for it either it pretty hard to find in older models i think mine is stuck somewhere in the dash.