It could be argued that they are both wrong, with the Boxhead being more correct than Bugsy.Don't worry @Krautman as a native born German speaker, you are unfortunately inferior in your own language than Herr Bugsmeister!
The Boxheeds themselves often make mistakes, and I love nothing more than pulling them up on them. A case in point would be that the Boxheeds very often confuse their two words for "the same". They have "dasselbe", which refers to one object, and also "das gleiche", which refers to two or more identical objects. So a typical example would be:
Boxheed: "Wir haben dieselben T-Shirts" - We have the same T-shirts.
Bugsy: "Nein, wir haben die gleichen T-Shirts."
Boxheed: "Die gleichen?" - The same?
Bugsy: "Freilich! Kannst nicht einmal deine eigene Muttersprache, Alter." - Of course! You can't even speak your own native language, mucker.
Cue red faces all round.
If only Germans could speak their own language like Bugsy eh?!
"T-shirts" should have been the singular "T-shirt," referring to the same (singular) print design or color of the multiple shirts.