Hello all, I have in my hand a T90 that has two small notches filed in the left side of the shutter opening. One is square, one triangular, and they're located about a quarter inch above the bottom of the opening. They resemble the identifying notches in the edges of sheet film. I'm told that Canon service put them there when the camera was serviced in 1992, at which time a PC socket was installed. Does anyone have an idea why these notches were cut? It seems an odd way, and an odd location (in the film path!) to say, "Canon was here!"