I think they did, they were originally for the (narrow) Pro Maxx upgrade to widetrack setup they sold, but tons of new ones still available on Ebay. I went ahead and bought another spare pair. If you want something much chunkier than stock, but don't want to spend $12 a set for Rpm's, these are an option.
Pro-Line 6008-00 Maxx Suspension Replacement arm kit for 6007 suspension kits
Price:
US $3.99
Shipping:
$1.92 Standard Shipping

Here's a search on Ebay for them, tons of them left
http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40