Board Thread:Rogue general discussion/@comment-27020644-20151201055147/@comment-13471981-20151201060007

Or, Otso Berg simply bought the medal in a gift shop while on vacation.

It's a neat theory, but the medal is not concrete proof enough - Berg very well may have got it somewhere to model himself after Shay, since he thinks he's such a good example of a true Templar, or to remind himself of that experience in the Animus.