Can you get under the front of the coach at all to read a number on the side of the bag?? I have a 2000 Beaver Marquis with the Magnum chassis and all four bags up front are the same. Cant tell you the numbers though I have one in the back 4 am looking to replace. I can tell you the bags are a Goodyear 1R12 starting numbers 12 inch bag. Once you receive the number look at this website for further bag information for the rolling lobe bag chart. Goodyear Air Springs and Suspension Bags
. If you bags are worn and hard to read spray some water on them and it will make the numbers on the side of the bag easier to read.
Make sure you notice how the mounting bolts are clocked in relation to the air fill port. A lot of different bags to choose from. If still have a problem at your end maybe I can check one of mine for a number might be the same. Let me know