Insert a very fine blade flat screwdriver at the 4 notches of the "wood grain" bezel around the radio. Gently press in and the panel will just snap out in your hands! This exposes the 4 mounting screws and off you go.
My OEM radio has developed a problem...the "tuning down" button was faulty and the radio would scan down the dial at the slightest movement down the road. Well taking matters into control, with the radio removed, I removed the front panel 4 screws, removed the circuit board attached to the front display, dissected the micro switch and the problem is fixed...big deal I cannot tune down...I can still tune "up" but the radio is now completely usable while driving. I saw a few OEM replacements on ebay but the condition was poor.
Hope this helps. Sorry for the one year and 4 months delayed reply!