There is a differance. LPG, (liquid petrolum gas)which is the one you are looking to get and natural gas. LPG comes into applaince at a higher pressure (37mb) and natural gas slower at about 20/21mb.
The two gases also have different properties. for example LPG is denser than air and natural gas is lighter. Anyhow enough on the gas lesson.
To answer your question, most cookers can be modified by installer, I.E reset burner pressure and change nossles on burners.
nossles and instructions to change over come with most/all cookers as nearly all cookers start life set as natural gas.
you can alsio specify LPG cooker from your supplier, which is probably the easiest thing to do.