Nordost Serial Numbers

Nordost always sounds good on my setup but unfortunately, I would prefer to buy them used. Apart from being cheaper, they're more likely to be burned in and boy, I really hate running in cables. So, I would be grateful if more experienced users could give me more information on their serial numbers. I have heard that the serial numbers are attached/engraved, whatever on the cable itself for higher end series and only on the box (printed or labelled?) for lower end series? Are these observations correct? And are there serial numbers right from the very beginning or did they start at a later time? I have thought of asking Nordost themselves but not being a direct customer, I thought it's better I ask here. TIA!

As a matter of custom Nordost have always been happy to validate a serial number of you provide it to them. 

As to where the numbers are on V1 Valhalla they were printed on a wrap around the cable end in some instances
Oh that's good, I'll write to them then. Right now, I would guess that the serial number should be on the boxes for the base and mid end models and probably on the cables themselves for the higher end ones
@folkfreak  last I heard Nordost was getting inundated with consumers calling to confirm if a serial # was legitimate....Seems like there were a lot of counterfeit and or re-terminated Nordost cables going around.  My Nordost retailer told me they stopped confirming serial #'s some time ago although a authorized retailer might be able to call and confirm it for you. 
Could be @ron17.  It was a few years ago that I had them provide this service for me. 
ron17 is correct i tried to get a serial number verified and told me that they stopped doing that.
I wrote to Nordost about a recent batch of Nordost put up for sale by a shop, whether they were genuine Nordost and I got a reply. However, my next question to them regarding serial numbers was not answered. It's been more than 10 days now. Kimber is far more responsive and helpful. Brett of Kimber generally reply within a day or two. Wonderful guy!
Just to muddy the waters there is also genuine Nordost that does not have serial numbers, even if it should. For example cable cut down from longer lengths, even if done by Nordost with their connectors, may not have a S/N, and certainly not if done by a third party. Plus the serial numbers can fall off -- I owned a Valhalla power cord which had S/N via a black sticker that got detached, while Nordost would accept the cable as genuine they would not generate a new S/N

Net net there is no substitute for close inspection and review of the offered cable -- most fakes are obvious if you have a copy of the genuine article on hand