The one thing that seems obvious to me about the signature aspect of these memos is even if they aren't a straight up forgery, since the documents have been photocopied so many times, couldn't it be pretty easy to physically cut and paste the signature (then white out any edge lines in the next generation of copies)?
And that's not even taking in to consideration what can be done with a computer and Photoshop.
Yes, bring on the originals. Examine the paper for the proper aging effects, the proper type head indentations, ink type,....etc...