I received this link http://nakina.net/cn/cn5.html from Calvin Monaghan off the resin car list. I couldn't find any info pointing to a number series for the Accurail 4400 series cars.  Dennis Storzek remembers door and a half cars being rebuilt. Joe Binish sent me scans of article in Mainline Modeler by Stafford Swain. He talked about those rebuilds, but only mentioned wood door cars. 
I might just pick a small number series of rebuilt cars off the link and let someone with proof tell be I'm wrong  ;  ))
CW Propst