While it's true anything made for graal is graal's property, the principle should still stand that you respect creators work, at least by crediting him. Especially as he is an ex staff member of your server and has requested for it to be changed.
You don't have to change it, but considering he must have done work for Ol West while he was staff, the least that could be done in repayment is to respect his wishes and edit it to something different.
Not much of the crown is showing anyway, it would require very minimal effort to make a new crown and stick the fire part back ontop

And it was removed as requested by the zone gangs leader if you are talking about the blue and black bandanna with the wing on it