Thanks for your feedback. I am thrilled to be able to look at a real Nain and not a copy from copy-cat towns.. I almost lost hope of being able to look at one :)
I was also wondering if the signature was a post production one, but after close observation and "forensic" analysis of the colour variation, I am thinking it is more woven inline.. it looks like the real Habibian sig in terms of outline (at least based on pictures I have seen in
http://www.oldcarpet.com/habibian.htm), but I agree, highly unlikely from the master weaver's workshop.