HOWEVER, IF YOU WANT TO INVESTIGATE THE SIGNATURES:
On this particular document (Memorandum For Record,Aug. 1, 1972) you will notice that the top of the signature is cut off and if you run a ruler across the bottom of the memo you will notice that the loop is cut off exactly where the bottom line of the memo is. You can't do that as part of your signature. That is a mistake. If you look at this memo: Memorandum, May 4, 1972 the loop is full, however a piece of the line is missing that could be attributed to copy loss or ink failure. But cutting off the top of a loop in a perfect horizontal break parallel to the bottom of the typed line is impossible.
This needs further investigation. It is clear that the signature was not a part of the original (computer generated) memo and was pasted on later.
Amateur hour at the forgery factory. Just do the ruler test.
The signature is cut off exactly where the bottom of the memo would run if you continued typing to the end of the page. That could only happen if the signature was pasted on later.
Or if the memo was pasted or placed over a copy of a real document with his real signature.