I just saw that post and thought I'd take a look at my own installation and compare. Well, what can I say.. seems like I'm missing even more than I thought :D This is what shows up for me, on a computer that's never been online. Not sure how much of the listed content is relevant for single player but now I feel that I might actually be missing out on more than just another costume.

I just received the following e-mail from GOG support, and the offline installer does appear to be updated. Does anyone want to test it out?

Same mail to me, so I'm curious too.

I'll just try the update from galaxy and see what happens when I start a new game while offline, but a test from a vanilla totally offline installation from scratch could be interesting, if anyone has the time/will.

Here we go again ;) Will try it and post.

Edit: The changelog makes me a bit sceptical though

"Update Content Drop #10 hotfix (28 November 2018)
Minor installer bugfix."

But maybe we will get lucky.

Edit: First step success - completely offline, DLC still shows in the "What's New" List. Now I have to play the prologue - offline.

Edit 2:
Edit 2: I am able to switch to the Badlands Rider clothes tab the moment I am able to access my stash and at start of the game it says "you received a new outfit". Still cannot change to it since the prologue is not over yet - but it looks REALLY good. No Galaxy Service and no connection at all!

Just to be 100% sure I will still finish the prologue.

Edit 3 (Final): Just finished the prologue - no Galaxy - no connection - DLC unlocked and I just changed into Badlands Rider Outfit!

Ok, I can confirm with my (prologue) test too that the update works :)

Seems like there was just a missing file "DataDLC39_1.pak".

And because the others two "DataDLC39_0.pak" and "DataDLC39_2.pak" were already there, it was most probably not intentional.

So, thanks GOG for the update :)

And thanks to all the supporters of this thread of course !! ;)

(Just to point this out if someone is interested, while the last update effectively show all the contents of the GOG version, the "mod" linked some posts above unlocks also things that are STEAM exclusive)

Congraturation. This story is happy end. Thank you. :)