A stone golem is created with a stone copy of a quarterstaff in his hand. Is this a natural or manufactured weapon? Does he get multiple attacks if it is a natural?
A Brass Golem serves as an exemplar; it's "equipped" with a brass falchion which deals damage as a Huge Falchion (it's a Huge creature) but it's considered a Natural Attack (ie. no iterative attacks, cannot be disarmed).
The description beneath the stone golem's statblock says the following: "While it may be sculpted to carry a stone shield or stone weapon such as a sword, these aesthetic choices do not affect its combat abilities."
So sculpting it to have a quarterstaff in hand wouldn't change its attacks.