Supra does use Kenwood but its a totally different model than the Moombas-no keys required.
Yes, you can see the two grey plastic pieces on the dash on either side of the HU. Look at my attached pic. The red arrows show the two pieces that pop off. You should be able to get a small flathead screwdriver into the gap at the top of the head unit. They will pop off in the direction that the yellow arrows are pointed. Hopefully that will get you taken care of.