The stainless fender trim was only part of the DeLuxe panel option 390B, it was not a "accessory" for the suburbans. Of course it could be purchased a piece at a time and installed on suburbans. A accessory item would have included all of the parts necessary to install the trim in one box with a single part number, all of the mounting hardware and installation instructions would have been included.
Also it was a Chevrolet only item used in 1947-1948-1949-1950-1951 (partial year) and 1954-55 1st series.
Moving on to 6 lug 15 inch artillery wheels. They were used on 1937-42 3/4 ton trucks and were a option on 1/2 trucks for the same years.
Here is a photo of a 6 lug 15 inch wheel that is for sale on eBay
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=4542401823&sspagename=STRK%3AMEWA%3AIT
The artillery wheels were never used on AD trucks.
1946 and later 3/4 ton trucks have a 8 lug wheel.
You will see the artillery wheels used on a lot of GM units that had the 6 lug wheels on them (but they weren't born there)
