as in for a shark fin/antenna delete? I've looked into this too and I have yet to find any true aftermarket cover or panel designed for this
there is a thread on these forums where some folks used some sealant and plastic to cover it but to me it looks a bit janky..but with a vortex generator think it would be an even better candidate to fit in a plastic cutout over the hole and seal it, just gotta make sure it is all sealed properly ^^