Looks like my order is (was) being held because of unavailability/backorder of the same color (anthracite) valve stems. After a couple of emails with Apex, we agreed that a substitution of silver metal valve stems was acceptable. I'm anticipating a shipping confirmation email at any time now.
An interesting discussion came up in our email conversation; Apex apparently thought my 2017 GTI Sport used wheel-mounted TPMS sensors. My wheels clearly do not have any TPMS wheel sensors (I'm on my second set of tires & had the valve stems replaced with the newest set) and my understanding is that the ABS system provides that function. When did VW go to the ABS system providing the TPMS function?