What is the go with the Matt finish, both my sprout and apex have these scratch like marks everywhere, not a scratch as such you can feel but I can replicate these marks with my finger nails and they don't seem to want to come out of the finish.

Boards have never been on sand or in a board bag

I used to sell the Thunderbolt boards but haven't since FireWire took over so don't have as much direct experience as previously. Perhaps it's an Innegra fibre used in the fibreglass cloth?

looks like the cloth moving in the resin, kinda common for composite boards and esp if they flex a lot.