U-boat with two deck guns (U-196)

[Shadowblade]

U-196 was fitted with six 53.3 cm (21 in) torpedo tubes (four fitted at the bow and two at the stern), 24 torpedoes, two 10.5 cm (4.13 in) SK C/32 naval gun, 240 rounds, and a 3.7 cm (1.5 in) with 2575 rounds as well as two 2 cm (0.79 in) anti-aircraft guns with 8100 rounds.

Is there a story behind the fitting the U-196 with two 10.5 cm deck guns? Who requested / ordered to add another deck gun? A request of her Kaleun or was it some experimental variant?
Were there any other WWII uboats armed with two deck guns?