i think all bottles that have those poi (larger fittings) 4 kg an bigger should have regulators may be corrected if wrong
You may be right but the determining factor is the appliance. Adaptors can be purchased to enable high pressure appliances to be connected directly (no regulator) to larger cylinders with pol fittings.
Depends on the appliance you are using, some are low pressure(regulator) or high pressure (no regulator), Rod
How do you which is which?
While normally small camping style appliances such as small camp stoves and lamps are usually high pressure (no regulator used), and appliances such as caravan stoves, webers and patio barbecues, room heaters etc are usually low pressure (need regulator), I would urge caution in drawing any assumptions as there could be exceptions.
Almost without exception however, fixed gas installations in caravan/RVs use a 4.5kg or 9kg (approx) cylinder and require a regulator.
In the case of portable appliances, it's best to check the instructions or consult someone who is familiar with the particular appliance. Getting it wrong could lead to dangerous consequences.