1stmh-
Per the parts manual for your coach (link
here, page 103 of the PDF), the part number for the Workhorse-chassis lower ladder is 161990-05-01A. The Freightliner-chassis lower ladder uses a different part number (161990-01-01A). You may have a Freightliner-chassis lower ladder.
As you pick through the Winnebago documentation you will run into the Workhorse/Freightliner differences frequently, I suspect. I have to do the same on the gas chassis coaches, Ford/Workhorse.