I'm not huge on paperwork because all of my snakes came from well known breeders. I just kept a written record of where they came from and when I got them.
When it comes to recessives, I would only buy 100% hets from someone very reputable and I have done this. Therefore, not all of my hets came with paperwork but I don't think it's required when you're positive of what you're getting.
The truth is, anything can be forged. This is why you should buy from reputable people who are known. Not some schmo on Craigslist who can not give you any details whatsoever.