A TFW2005 board member has posted the image (left) of four weapons that were spotted at a Pontiac, Michigan location being used as a storehouse for Transformers 4 production while they film in the state. These 4 are in addition to one that Mark Wahlberg's character has been spotted carrying. Exactly what the weapons are for remains unknown but their scale indicates they would fit fairly comfortably in a Transformer's hand. Any case speculate away in the comments.

Update: Picture pulled at the demand of Paramount Pictures. Which has the side effect of confirming that the 4 sword like weapons are part of Transformers 4 production.