I too had a hub cap (front) come up missing and the price of a pair went from $520.00 dealer, to 139.00, vendor for Winnebago, a pair.
I then contacted a local heavy trucking parts store, Truckin-stuff, here near San Diego, bought 2 new stainless crome caps for $5.67 each.
Call them, their online. www.truckin-stuff.com
2002 W-22 266"wb, Winnebago Chieftain 39T, UltraPower, Koni's, Helwig bars, Nuvi 660, Sirius, Scan Gauge II, Sentry TM. 2003 LW300 Saturn toad, Sterling towbar & Apollo brake. And Hannah the Princess and Stevie the Dude!