It looks like the slinger, or rather the remains of it, to me as well. As you saw in ETKA, they don't sell just the slinger. The same part is in every bell housing back into the bay buses, though, and could be tapped out of one and installed in another. You'll want to inspect the input shaft both where it would have contacted the slinger and also at the end where it goes into the pilot bearing in the end of the crankshaft. You'll also want to replace the pilot bearing.