Hi Paul. The "no photography" sign at Jefferson and Taylor was likely due to the Army's use of Pier 45 as part of the Fort Mason Port of Embarkation. I've seen lots of photos of soldiers waiting at the pier shed in '42 waiting to board troop transports.
I don't think the Sutro Heights cannon are in a different position. There were two guns up there: one near the stone staircase leading down to the perimeter road and the other closer to Adolph's house. (John Freeman and I found Sutro's receipt for purchasing the cannon at the Public Library.) The gun that appears briefly is the one closest to the house.
What surprised me was that the cannon AND the statuary were still there during WWII. Assuming all this footage was shot around the same time, that means the cannon and statues survived well into the war. I always suspected they were removed from the parapet not long after Pearl Harbor.