thats the width. It should be stamped somewhere on the back of the wheels hub or spokes. You may also have a sticker on the inside of the rim.
Should look something like 19 x 9.5J +35 etc. 19 being the rim diameter, 9.5J being the width and a + or - number being the offset. Looking at the pics of your rims you would have a positive offset on those, probably around +30 or more. If its higher than +35 you will need to run spacers on the front to clear the front control arm, if its lower than +30 you will need to roll your guards.
So basically it will be perfect at 9.5J + 35 to +30 and you wont have to do anything other than fit tyres!