David, this is the pen you unknowningly reminded me to buy. I can't believe it went unsold for so long.
The only information I have found about it is from the website of the late John C Loring:
"JFK or LBJ? Parker 45 'Demonstrator' perhaps the first Parker 'bill signer' - I am advised (second hand) that a gentleman who worked as a Congressional Aide saw President LBJ sign a bill using the Parker '45' 'Demonstrator' with an eagle seal pictured at page 10 and then was given the pen by LBJ. Thus we now know that notwithstanding the non-presidential seal it is a 'presidential' pen that entered the White House either during the JFK or the LBJ administration and at least had limited use by LBJ as a billsigner. While I could not find out which bill or date of signing, it would seem probable that it occurred during the period LBJ was using the Esterbrook 'bill signer' and before he settled on the Parker Eversharp felt tip. Thus while it has long been believed that the Parker Eversharp was the first of the Parker bill signers it now appears that that 'honor' belongs to the Parker 45 'Demonstrator'."
The pen he had is pictured on the sale page, the seal on his is blue while mine is gold.
Does anyone have any more information about these? Has anyone even seen any others?