The rollback will take all characters back to before the beta, so if it was made since then it will not be there afterwards.
Consider it as everyone going back in time. All the stuff we owned when we were younger is there as it used to be, but all the stuff we bought as adults isn't owned by us yet.
Or maybe something like killing off your parents so that you never exist...
The BetaTestCash doesn't exist as a particularly useable ship, it simply gives you a lot of cash to move to another character. Someone could easily use billions of their own saved money to do the same, it doesn't make any difference to the player database.
