Leo: Given the sentence "Period re-inactors sit on grass bales and talk while others in more modern attire sit and walk in the background." is it true that "Period re-inactors are dressed in period clothes."?
Mei: OK, So, let's think first...
Me:
Period re-inactors tend to be dressed in period clothes and if others around them are in more modern attire it would indicate that in this instance the re-inactors are in period specific clothing.
Thus, the answer is yes.