Per mil spec, the minimum rivet pitch for a -3 rivet into a dimple is .563 inches.
The reality is that it will be fine just dimpled and plugged with a rivet to nowhere. That hole is so small that you could likely be just as well off to just deburr it and leave it as is. Vans will likely tell you one or teh other of those two things.
But, any time I deviate from the factory engineering or industry standard (ac43.13 or MIL-R-47196A) I call Vans and document the answer, just so that if I ever sell this thing, I can honestly say that I have engineering coverage for anything off print.