Audio Systems: radio replacement, chevy silverado, proper interface

Question
Hello, I have a 1996 chevy silverado, and been having problems with my cassette player in my radio.  I purchased a used one out of a 98 siverado and they look very much alike.  My question is, what is the easiest way to replace the radio.  There is no 1/8" holes on each side. just the trim.  My guess is the trim pops out to get to the radio, I tried very little to see if it does pop out and it was on the verge of doing so, but I popped it back in until I got word from an expert.  Is that how it is removed/replaced?  Also, there is no bracket for the radio, the seller said it just fits in there.  Thanks for you help, Bruce of Cedar Rapids, IA

Answer
Yes, basically you have to pop the trim panels off, then the rest is pretty easy.
Beware that the newer unit may NOT function properly when it is plugged into the older harness. Check the plugs and wire layouts (to be as sure as possible) for a proper interface before you plug it in (This may be difficult if the new one is not with its' vehicle now). The plugs may look identical, but the wire layouts in them may be different.

You will see how it is held in place as soon as you get the trim panels (s) off.
Any mounting brackets it may need should be swappable to the newer radio.