...not sure why this thread veered off into Type II U-boats, but.....
Of the 6 Type VIID U-boats built (U-213 - U-218), there appears to have been one boat that was modified from the original, as-built configuration of 1 x 2cm Turm gun. The U-217 was modified in 1943 to carry the 4 x 2cm Zwillings.
The only photos of the VIID Turm that I came across in a quick search of my 'library' were of the 1 x 2cm mount. Having said that, a large number of photos and documentation did not survive the war......so one could reasonably take some liberties in building a model with something different if that's what you wanted to do.
I would be surprised if these guns were the same, or even based on, the similarly named ones used by the Wehrmacht. The naval variants requiring special consideration for being submerged. Which makes finding gun kits that are accurate difficult.
-hope this helps,