I just received my 54mm scale (1/32) 88mm deck gun with 3 figures made by Andrea Miniatures
sold by Squardron.com
They are in Texas, They only have one kit left......I paid $165.00 dollars. This is a very good price..
The gun is white metal and the three figures are also..
Very detailed kit and as far as I know this is the only kit available in the US.
I don't know of a 105mm gun kit.
If you want to view a photo do a search using "Type VII U-Boat Deck Gun and Crew 54mm."