what are the markings on c7 canadian buttstocks if any?I'm trying to find out if the one I want to buy is the real thing,can anyone help me out?the seller lists this as a colt c7 stock a1 length with
a2 buttplate,cs marking on right side near front ,is it bs?

there are no markings on the either the full stock or the new OD Carbine stocks.  
and there would be little chance that it would be the real thing since no c7 or parts of them where ever  demil.  So if it is real it would be stolen.

It's probably one of the older production "Colt Short" buttstocks that was an "option" on the Canadian C7.  Being a short bastard, my issued rifle team rifle (back in the early 90's) had one of these affixed to it by our team weapons tech.  The stock should have a raised small "S" captured within a capital "C" on the ejection port side of the stock wrist - just behind where it attaches to the lower receiver.  Wish I had a pic of it, but that's the best I can do to explain the marking.  It is the same size (if not just slightly off) as an A1 length stock, but it is in fact made in the same shape/configuration and materials as the A2 stocks.  The buttplate assembly is the same as on the A2.  They aren't made anymore, and the ones I've seen for sale recently are commanding pretty steep prices (for an A2 type stock that is).  Hope this helps....

hsld.

BTW, anyone know where I can pick one of this puppies up in NIW condition for a good price....

Here's a photo of the short A1.   Debut on the Colt Sporter Lightweight (R6530) in 1991.   I put my name on the photo because the last time I posted it here, someone stole/cut/cropped it to sell their items on Ebay.   At least you can see the CS.