Matt_Boyd sent out a tweet yesterday that he spotted yellow production signs with "E7" written on them near Raleigh Studios in Pontiac, Michigan. olv responded by noting that those same signs were used during Transformers 3 filming. This should leave us to believe that some type of pre-production or filming took place in Michigan on March 28th for Transformers 4. These signs have also been used for Revenge of the Fallen and the first Transformers. To the left is a photo from the Revenge of the Fallen set.