I've learned that ANY celebrity autograph needs to be authenticated and have a COA with it if it's a high-bucks item. Many "celebrities" (especially the one's with "fan clubs") have a secretary sign many of their "mail-out" type pics. Even Presidential photos sometimes have "bogus" signatures. There are also COPIES of signed photos as well as some rubber stamped "signatures".

As for the "same pen" ... that is a common thing. Most autograph hunters hand the celebrity whatever it is they want signed (ball, program, autograph book) along with a pen/marker to sign it.