Yes, generally using M5 x 25 steel ‘penny’ washers; however, if the Buttons/Fixes are binding due to angular misalignment, it is best to use washers that are within the ‘footprint’ of the Button (i.e. Ø18mm or less, for example part number 1000750000VR here) which will allow more angular tolerance. Bear in mind that spacing off the Buttons will increase the bending forces on the button fixing and reduce its weight carrying capacity.