They aren't just Agilent labels.
I didn't mean that so literally.
I think it would be worthwhile to counterfeit them, there's a fair few selling on eBay, as well as most other auction sites. I've purchased a product before that came with a similar set of bumf (manual, warranty card, box, etc), found it was totally fake. It was only when I got it side by side with a real one that it was really noticeable (and subtle even then, you had to know where to look).
One suspicious thing I noticed is that every listing I saw on every Chinese website these are listed on (eBay, aliexpress, taobao, etc) that shows the box has a datecode of 20091102. Either there was a huge batch that went to Chinese sellers, or the guy who made the counterfeit labels didn't think the move the batchcode around.
The Linux driver code for both is the same.
Because it's a clone. It needs to appear the same so Agilent software will work with it.