Regarding feet for the 3478A, there is a more readily available alternative solution, if you have the same revision as mnementh.
Specifically, on the front panel, the bezel is plastic and has four cleats(?) that hold the front panel in (e.g., one is between the up and down arrow buttons and another below the calibration switch):
On the rear panel, a plastic bezel covers the rear edge of the slide-on lid:
Both of these bezels are predecessors to the ones used on the 34401A and, hence, you can fit the front and rear bumpers from the 34401A, 34410A, 34411A, 33120A, 34461A, 53131A, etc. on the 3478A. Doing so eliminates the need for the original plastic feet as the bumpers have integrated feet. Of course, without the ability to mount the corresponding handle, there's no provision for a tilting bail.
Although the front alumin(i)um bezel of the older version of 3478A is similar, and could use the front rubber bumper, it doesn't have a rear bezel to grip the rear bumper. But that shouldn't be a big problem unless you move the meter often.