1) that cloth fabric cloth is not ‘correct’ for the 5E3. 2) yes, that cloth affects the sound that one hears. I once had an old tweed Pro that has that brown cloth grille...all original and excellent condition. I had another baffleboard built for it with the later brown and gold grille ‘cloth’....which was made to allow the sound waves to pass through with less effect on the sound waves...as opposed to the earlier grillecloth which is effect just cloth. The difference in sonics is amazing after I installed the new cloth, it was interesting to listen to the amp and then hold the old baffleboard with the brown cloth in front of the amp for comparison.....Drastic difference in the sonics. There is a reason why amp manufacturers and speaker manufacturers devised new and more sonically transparent grillecloth all of those decades ago.