If you start the computer's Steam Launcher app and log-in to start the game there, it will say which it is. The icon in the game folder itself always says "SH4.exe", but if you right-click on that file, and choose "Properties" from the context menu, then click on the "Details" tab, you will see a "
Product version:" line about the middle of that little window. The "Gold Edition", or "U-Boat Missions Add-On" both will have "
1,5,0,0" in that box. The older version will show
1,3,x,x, which signifies I am not certain as to which of the various v1.3 of the game they are using... lol - The Steam downloads should have these images on their starts in the Steam app on your computer:
Silent Hunter: U-Boat Missions Add-On (updates the below version)
Silent Hunter: Woves of the Pacific (v1.3 of the game)
It looks the same on there still, so same ole same old... you have to buy two games to get the one...