SH3 would be v1.4b (hopefully I have the correct number) for the latest version, and is the version required for almost all mods. It will usually show as "Product Version: 1.4.0.1" in the Windows Properties for SH3.exe
SH4 disk versions for the most part are v1.3 if a "Silent Hunter: Wolves of the Pacific", while the "Gold Edition" is v1.5, and is usually "Silent Hunter 4: Wolves of the Pacific". This does not always apply though, being dependent upon where you purchased from, and what country or "region" you are in. There is an "official" patch to take any version of v1.3 or prior of the game to v1.4, which is still just a "US Pacific" version of the game. That will show as "Product Version: 1.4.0.0" in its Windows Properties. A Steam download will show as v1.3 updated to v1.4, and has a 2nd download for "UBoat Missions Add-On" to bring their version (and their version only) up to version 1.5 - So you might need to make 2 purchases on a Steam download to get to v1.5 which is what most mods now use. There is an Amazon download available (Silent Hunter: Wolves Of The Pacific - Gold Edition), as well as a Ubisoft "UConnect" download available (also a Gold Edition), which is currently the least expensive way to go to get that v1.5 of the game. They will all show as "Product version: 1.5.0.0" in their Properties page. DRM is constantly changing though, and disk versions are very difficult and expensive to purchase. There are very few mods for v1.3, and few more for v1.4, with most mods written for v1.5 of the game.
Then there is Silent Hunter 5, of which, the only viable option would be v1.2 and then mod it. Version 1.2 will show as "Product Version: 1.2.0.0" on the Windows Properties page. One has to be very careful of DRM with SH5. Purchasing a used disk is a waste of time and money usually, since the disk is most likely already registered to another user, and cannot be re-registered. I am not familiar enough with the disk version myself, and I do not know if a person can break the link between the first purchaser and the disk. I have a Steam version of the game, and I can mod that for one, and only one mod, of which I use TWoS. I want to try Sober's mod, but it does not work with a Steam version. I also have a UConnect version of the game, and that does not work with TWoS anymore, unless you use THEBERBSTER's fix. That might also function with Sober's mod, but I have not tried.
All of this information is from a Silent Hunter 4 player, and your mileage may vary considerably with all three games. I enjoy all three games, but I definitely spend the majority of my time with SH4, and currently probably over 90% of my time there... I do tend to dote on one game or the other, and my SH3 time have been 'stealing' from SH4 lately. I am reasonably certain to back into SH5, trying to hone my ladder climbing abilities soon, as I attempt to walk through the boat, which I think is very cool. I am not a very good skipper though, and apparently contribute greatly to the enemy's cause instead - but I do have fun... If I misunderstood your question, or accidentally mislead you, please forgive me.
