This plaid looks like it’s really nice. It’s either a blue or grey toned plaid, with a brighter thin strip running through it, and overall appears to have a sort of red glow to it that I can’t quite explain.
In Advanced Thanatology (13x05), Dean wears this shirt when he and Sam go to investigate the haunted mansion, and Dean kills himself temporarily and meets with Billie – he keeps it on until the end of the episode when he and Sam see Castiel again.
In Tombstone (13x06), Dean continues to wear this shirt until they all leave the Bunker to go check out the case in Dodge City.
In ScoobyNatural (13x16), Dean wears this shirt in the very first scene when he and Sam save the pawnshop owner and get the TV as a thank you gift.