This may help you find out the manufacturer of your wheel liners. Go to
www.winnebagonind.com and click on "resources", then "manual and diagrams", then "Parts Catalog". Click on "serial parts list", click on the model year of your RV, then enter the
last 5 numbers of the serial number of your RV, and click "search". The serial # should be on a label somewhere near the driver's seat, possibly on the door.
Scroll down on the parts list for your specific RV to, probably, Liner-Wheel (that's how ours is listed). Copy down the part number, then go back to the Parts Catalog page on the web site and click on the year of your RV to get the catalog for that year.
In the index of the catalog look for wheel liners, go to that page and start searching for the part number of your wheel liners. The different parts, including tools, should be listed there.
Also, if you give that wheel liner part number to Winnebago, I would think they should be able to tell you who the manufacturer is.
I hope this helps. Good luck!