TX law is very specific about where reg. numbers are supposed to be placed, which is below the bondline, just aft of the nose. That being said, most peeps down here have the numbers above the bondline on the hull (cuz on a standup below the bondline is stupid). Water cops will usually mention it to you if you have it on the hood (they're supposed to be on a permanant/non-removable part of the boat) and seem even more likely to tell you to change it if you have it on the pole.
Now, I've not seen anybody actually get a ticket for them being in the wrong place, but they will say something, especially if you give them an excuse to stop you (as opposed to, they're just doing routine checks and see they're in the wrong place).
Beyond that, I'd bet they'll have to be custom numbers to look right on that boat.