Laertes has a zipper down the back of his costume.
When Hamlet is at Ophelia's grave and shouts "I loved Ophelia", the person holding him down has a modern plaster (band-aid) on his finger. It is only briefly visible as the person hides this finger for the rest of the scene. In the same scene it can be seen that Hamlet has metal grommets on the cuffs of his jacket.
Towards the end of the "What time is it?" scene the boom mic is clearly visible in the top left hand corner of the screen.