Hi all, I am just building the Zvezda bf109 f4, after applying a coat of primer on close inspection I have noticed a small 'socket' on the right hand side, as you fly it, halfway between the cockpit front and the machine gun openings. This socket looks as if it needs a part but I can find no reference to said part and fitment in the instructions, although I have found a part that looks as if it would fit (A59) does anyone know if this is correct?