What...? So a guy posts that scroll is 180 years old and it would be alright with you to buy it based on that info only to find out it had been re-hung using methods from 2009. Why would you even bring this up?
Oh thats right the world is full of liars, cheats and thieves. Anything for an opposing view ehh?
I brought it up because scrolls are often changed, in fact many now are attached to the backing in such a manner that they can be changed, common practice, especially with kakejiku, but almost never with byōbu or shohekiga.
I have no idea how old the scroll is, neither do you, but I do know that it is the actual painting itself that is in question, not the rod (ikugi), end knobs (jiku), or backing. The truth is that many antique scrolls do not automatically come with the hanger. Another truth is that often the hang bars and the backing have nothing to do with the actual age of the painting itself, in many cases.
Yes, it would be alright to buy an antique scroll that is on a modern hanger, its not the hanger that is being bought or sold, it is the painting itself.
I also know that a close up of the calligraphy and the chop would help any one who does know about such things date the painting.