Natter, how does these markings look for the G7a (T1) LUT II?
I don't know about the stripe on the rudder: The description doesn't say wether it's vertical or horisontal (I have seen vertical stripes somewhere, but I don't remember it's significance - might have been unrelated to the GA). Compared to the drawing the "L II" text should be slightly larger/bolder, but I bet this were applied differently from one arsenal to another... I reckon it's as good as you can get it, given the information at hand.
NB: Be aware that your torpedomodel is a standard T1 without Fat or Lut, so it's not correct with "L II" markings on it..!
Btw: The screws for the head seems different from the screws joining the aft-section and the airtank (hard to tell from the low res. image)?
Was were any markings for the LUT I?
I have not seen any reference to it, but I assume it was (maybe similar to the TIII - ref. the merkblatt I posted earlier).
Was the center of gravity marking on all torpedos?
Probably not... I have seen lot of photos showing no markings. I have not seen any documents with guidelines for this, and have no idea if there was a certain colour to be used.