Perhaps they were left behind in a "metaphoric" sense, but I highly doubt that Gary left anything useful for T$R--if he had, they would have used it to continue their charade of "business as usual". And judging by the Gord books, Gary had a very specific idea as to how at least a couple of those new classes were to be done. ^__^
Technically, it might be impossible to cover because the class as presented by Kuntz was very third edition andy ou'd have to trim all the default skill debris and decide which skills would fit as an ability like the barbarian. Another factor is the download had errors throughout so its hard to figure out what goes towards what clan. Speaking of that its kind of a spin off of the old Jon Pickens' berserker article from DRAGON #3 (OCT 1976).
I've had some variant berserkers over the years but nothing is iron clad. Its mostly scribbles about different berserker groups from the campaign and the different bonuses of each. If I were to make a berserker class write up that might take a while to iron out so I might put that on the schedule for next year.