Board Thread:Rogue general discussion/@comment-27020644-20151201055147/@comment-2112031-20151201124655
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.
I'm pretty sure that he did know about Shay prior to the Modern Day portion of Rogue, given how he seemed to revere him throughout the game even before we reached the part where Shay joined the Templar Order.
I don't think the Viking Armor belonged to Otso Berg's ancestor. The ancestor, described by Otso Berg as "a young man", was present at the Viking raid of Lindisfarne in 793 in Northeastern England, whereas the Viking Armor was recovered by Shay in North America.
I also noticed they misspelled the name of the Island. Calling it "Lindsifarne".