Since the arm is already mounted why don't you raise it to see how high it goes? The platter you have now is 1 inch high,find out the height of the new platter and see what what the difference is,you might not be able to lower the dust cover. I tried this years ago with a mk4 platter and it never worked out. I suggest if you want to upgrade with out any hassel try to find a mk3 platter. Good luck!