Having printed a few POD books for Classic Traveller, it's definitely work. For one, you need a good quality scan of the book. Even though I own the Classic Traveller CD-ROM, some of those scans contain quite a few things that needed cleaning up. I ended up borrowing a copy from a friend and re-scanning Book 4 - Mercenary. I then redid the cover from scratch. You need to get the whole thing to fit into the POD publisher's template. Getting it the right size, making sure there are no artifacts, and making sure you center all the scans on the page is work. If it were my full-time job, I think it would take me about 2 business days of only working on one LBB to get it "print-ready" for a POD publisher, assuming I had a good quality physical book to scan in.
You're also looking at resizing the books. None of the Classic Traveller books are of any "normal" size by 21st century printing standards. So, any large book needs to get redone as either US Letter or A4 books. And the LBBs would probably need to be US Digest size. US trade size or A5. Then you have the entire issue of saddle-stitched versus perfect binding. DriveThruRPG will not do saddle-stitched anymore. And the POD publishers that can do saddle-stitched books usually limit them to 48 pages.
So, if you want POD Classic stuff, it will not match the existing classic-era material.
Also, does Mongoose (or even FFE) have good quality print copies they can scan in? If they don't, they'll need to go "eBay shopping" trying to find a copy good enough to scan in. When FFE released the CD-ROM, the world of computers was quite different. File size was very important; the smaller, the better. In 2025, file size matters less. Good 300 DPI or 600 DPI scans of Traveller books no longer posses network bandwidth or disk size issues anymore.
If I were retired, this is something I would happily do as a contractor for Mongoose. But sadly, I'm a decade away from that point in my life. And having redone a few of the Alien Module covers, I have to say, those are a lot of work to get looking good enough for POD.