We do carry SO1 and SO2 for the Kilrathi Saga version of Wing2, but this doesn't work in the DOS version, which is what GoG's version uses.
Well, you know... actually...
Back in the days when I first encountered Wing Commander (pretty late - it was 1997), I was living in Papua New Guinea - a big tropical island nation with no notion of copyrights (seriously: it's not that there was rampant piracy, but rather that there was no such thing as piracy, because copyright laws were officially not enforced). So, all I had was pirated copies of WC1, 2, and Armada. Each of those was pirated from an original copy that one of my friends brought into the country, which was basically the only way you could get games (because there wasn't even a pirate games trade! You couldn't even *pay* someone for pirated games!).
Then, along comes the internet. Stuttering at a blistering pace of about 5kb/s, that's true - but it works! First thing I search for is Wing Commander, and it seems that KSaga had just been released, and offers free downloadable add-ons. At the time, I was starting to mess around with HCl's ship & mission editors, so I figured they're worth the download - maybe I'll be able to somehow add new add-on ships to WC1/2?
To cut a long story short: you can get the KSaga add-on data files to work with the original WC1/2 executables, to a limited extent. The one that works most perfectly is SO1 - there's no problems with it at all. SO2 is just fine right (except for the Morningstar's nuke, which you need to edit into another weapon) until the very last mission - sadly, the Morningstar jump is a new feature in the executable, so you can't jump. I got over that as well, I simply replaced the Morningstar with a Broadsword, and edited the Broadsword to have more or less the same specs as the Morningstar
.
IIRC, with WC1 it was a bit worse, because all the ship data was in the executables, so none of the new ships worked off-the-bat. I do not remember to what extent I was able to get the WC1 add-ons to work - there must have been some limited success, but very limited.
All in all, I was pretty glad when, at the end of that year, we went back on a holiday to Poland, and, passing through Singapore, I was able to buy KSaga, WC4 and WCP all in one trip. It was nice to get WC4 and WCP, but above all, finally being able to play the WC1/2 add-ons properly, that was awesome. Boy, was I disappointed when I realised what a lame product KSaga was. Also, it messed up my father's computer, because KSaga's DX2 insisted on installing itself right
on top of DX5.
Good times.