You need new air bags already? They should last a lot longer than 11 years.
To get the number, you'd need to take a bag out as the number is on top of the bag.
REV Group may be able to get those with your VIN or model. They have however changed hands several times around that time frame and usually don't support previous coaches.
Or you can contact Veurink's RV with your VIN # and they will know what bags you need: https://www.veurinksrv.com/we-provid...xparts_request
They will respond with their part number but they are probably 2x the cost of air bags in other places like Michigan Truck Spring - https://www.truckspring.com/
But once you have the Veurink's part #, you can backtrace that to a Firestone # or whatever bags you may have now. Then go to their web site or a local truck parts store.
If that does not work, check back here.