The passenger armrest is available as a kit.
The part number and installation guide are posted at
www.ptdiy.net
I wrote that guide many years ago.
No PT would have a passenger armrest if the Chrysler engineers hadn't asked to inspect my modified PT back in 2001. I used the armrest from the right-hand-drive export PTs to favricate a passenger armrest. The Chrysler engineers spent a lot of time inspecting my mod, just to see it become standard on 2002 & newer PTs.