Volvo Repair: 1993 volvo 940 radio removal, 940 radio, square holes

Question
trying to tkae the radio out of this vehicle to install another. I am told that the radio rides in tracks and simply sliding in putty knives on each side will release the clips but this doesn't seem to work.  Do I need to remove the face plate first?(if it is removeable)  Is this correct removal method?
thanks for your help

Answer
First, sorry for late response.I am in SW Florida and if you do not know we were just hit by  Hurricane Charley Friday and I just got power 30 minutes ago.


at each enad of the face of the radio are 2 small square holes insert a small screwdriver into the hole and pry outward away from the face of the radio while pulling the radio with the other hand.do this on both ends