And a picture - seems that a PO reinstalled the flasher sideways last time
That bracket, C1TF-13351-A, was designed to mount the flasher either vertically or horizontally. The 66 Electrical Assembly manual shows vertical. Sticking your hand up there to check wiring or replacement was not easy, so if it fit, good.
Speaking of flashers, there are two type, the turn signal type says "two bulbs" on the can for either the left or right hand pair; the emergency flasher says "four bulbs" because all four bulbs are lit.
Jim