Regulators for flammable gases are built differently (and cost more) than 'neutral' gas regulators. Using anything other than the proper regulator on an O2 tank will create a fire/explosion hazard. A tiny leak in your CO2 regulator means you'll waste some gas. With oxygen, you'll blow up your house.
It is important to ensure that the CO2 regulator is securely attached to the CO2 cylinder before you start. covers solely the use of single gauge regulators that come with most kegerators; however, any regulator that works with a CO2 cylinder fitted with a CGA-320 valve will serve the same purpose.