Simon Morris did some research on the balkon geraet making a list which boat were fitted with same, I cannot see that U-453 was ever fitted with a balkongereat. U-995 did not have the Balkongeraet during WW2 , and in my time, however the geraet was fitted latter part of the 50ties and was eventually removed on the museums U 995. U 995s Balkongeraet fitted end 1950 and a copy of Simons execellent drawing is below. On the VIICs it was fitted as from frame 79 up to frame 92.
Tore