Use this information however you see fit

Anyone know if this is true?

It is. I've kinda been meaning to get into it as a low-effort artistic hobby. However you're more likely to find matching puzzles made the same year by the same company than if you try to use puzzles from different years or different manufacturers (yes, some manufacturers share stencils).
- That's what I was thinking too, silly little art hobby. It makes sense, why would they retool for every design.
Sometimes, with caveats (I researched this a while back). tl;dr: probably yes, if you get puzzles manufactured by the same company around the same time.

There are "puzzle companies" that are actually just design studios who farm out the manufacturing process to a puzzle printer. Depending on the printer, they're very likely to reuse puzzle dies even between design companies; so you might even be able to remix two puzzles by different companies, if they use the same print company.

Certain high volume printers rebuild their puzzle dies from scratch every so often (so the design would be entirely different depending on which print run you're working with). Ravensburger in particular had a thing on their website (it might still be there) about how they can't get you individual replacement pieces because they've almost certainly already rebuilt the die since your copy was printed. And most companies end up just replacing the entire puzzle if they leave out a piece.

Some puzzle companies make puzzles where the design and the cut are related somehow (Magic Puzzle Company built a whole line on those). Those are unlikely to be reused between designs, though you do end up paying extra for them.

Even if you get a pair of puzzles that were cut using the same die, they might not line up the way this image shows. If the die was removed and flipped around between one puzzle's cutting and another, the cut would be "upside down" on the other and they would fit together in a very different way.
- Pretty cool stuff
It seems to be true.

Jigsaw puzzle companies tend to use the same cut patterns for multiple puzzles. This makes the pieces interchangeable. As a result, I sometimes find that I can combine portions from two or more puzzles to make a surreal picture that the publisher never imagined. I take great pleasure in “discovering” such bizarre images lying latent, sometimes for decades, within the pieces of ordinary mass-produced puzzles. As I shift the pieces back and forth, trying different combinations, I feel like an archaeologist unearthing a hidden artifact.
I got a set of ten puzzles. There's three different sizes/piece counts. Each size uses a singular die. I ended up doing one puzzle on top of another and every piece was the same. Buying a set seems like a good way to get multiple prints cut from the same die if you want to intentionally do something like this.

Also the same camera angle, color palette, gradient, time of day and perspective Depth. We really are creatures of habit huh.

To be fair, the horse part is just green and brown. The sky and most of the color palette is from the locomotive puzzle. Not sure about gradient or time of day. So to me, the only real similarity is camera angle and perspective.