Jase.. Quick answer....Yes. Depending on previous treatment, you may find the inner face of the hardened worm a bit ragged. This washer serves to position the worm above the oilpump drive spindle and provide a more even clamping force against the timing pinion, rather than just gouging into it. Chamfer goes towards the timing pinion to clear the radiused change of shaft diameter, as already noted.
Never considered if the original part was hardened, see earlier posts in this thread, but you can bet many motors are happily running around with a plain washer from the useful box. Any washer is better than no washer, so take your choice as to how you source one.
Swarfy.