Depends of the what the rules say and the judges say and if the opponent rises a complaint for example Tornado VS Hypno Disc.

In that case Team Hypnodisc said that the interchangeable weapon that Team Tornado was going to use originally was a defensive item not a weapon and the Judges agreed and they had to swap it. Tornado still won but it is a example.

TBH as long at it still falls withing the size and weight set out by the rules it should be fair game, and it could of ended up like Concussion which lost due to it wheel guards.