The speaker grill comes out with two counter sunk screws driven through top. Be very, very careful with these, I suggest you use a #2 stubby and don't try to actually remove the screws: instead back them out a little at a time on each side so that the speaker grill comes up with the screws still attached. You will see what I mean when you get in there, you just want to avoid nicking the wood by pulling the screw heads up and through the fragile wood slats.
Now, the speaker comes out with four flat heads, and with it all out you will find you have accomplished very little in terms of gaining access to anything. What are you trying to do?
Best,
Greg
'64 230sl, fully sorted out...ooops, spoke too soon