The spacers I have inspected so far have all been flat. A chamfer doesn't change thickness at ID but does taper away at OD so there may be an orientation for some applications to some end. But others have observed the same 'excess' end play with a spacer (versus the old method of pressing to a stop created by shim stock):
Chevy Talk
and have even suggested machining/sanding the spacer down to shop manual specs.