At least as a bonus material?

I wasn't even aware that GOG had finally switched over to using ScummVM for Starship Titanic. Cool! As to your question, I haven't tried it myself but apparently GOG Galaxy has the option to download earlier versions of a game. If so, you'll likely be able to download an earlier pre-ScummVM version of the game if you're really interested.

Thanks, didn't think about this feature!
PS - if anybody interested why i seek original version - "Scummvm ver don't support the QSound library the original game used for simulating sounds in 3D space to output to standard stereo. We just do a very basic reduction of volume based on sounds' distance from the player.." not a big deal, but still bummer.

It would have been nice to properly re-implement QSound as well, but at the time I'd already spent over a month (or two maybe?) just reversing all the 3D library and floating point calculations for just the one single starmap puzzle at the end of the game. After that monstrosity, I was in no mood to also reverse QSound when a bodge would do nearly as well.

Though I did set up dummy methods in the engine that exactly match the methods exposed by the QSound library. Since it was a third party library, it'll be easier should anyone want to take charge of doing so in the future.. they'd just need to properly implement the methods.

Thanks for your work!
BTW - i successfully downloaded earlier version of ST with GoG Galaxy.

Hopefully at some point the original engine might be able to be applied but stuff like that is always tricky, and it would be time intensive. I know Riven doesn't use the original console, which sadly removes a really cool easter egg. I'm of the mindset the things should be preserved as close to the original as possible, but again, it's a matter of time and effort.