Yes, more or less. If you put a mod for v0.12 onto a v0.13 game, it is very likely you will encounter issues. The goal of the rebase is to take mods for old versions of the game and make them functional on newer versions, though it won't do anything for new content.Let me rephrase and see if my understanding is correct:
1. if you simply put the mod for v0.12 into the v0.13 game, it may not even start, or it starts but return some image errors.
2. the rebase mod tries to fix those problems.
3. the rebase mod doesn't do any thing to the new content, so if the v0.12 game has 15 scene galleries, the v0.12 mod unlock all of them, and if the v0.13 game has 18 scene galleries, the rebase mod can only access 15 of them, right?