That's how it worked with the '94 ban, but I'm betting they'd prohibit sales of any after the effective date if they enacted a new one.
They're extremely unlikely to overturn a previous ruling, nor are they likely to hand down a new ruling that contradicts a previous one. If SCOTUS is constantly flip-flopping like the rest of the demagogues in congress, they become wholly irrelevant.
As long as we keep fighting the good fight, 2A is relatively safe. Seriously, we enjoy more 2A freedom today than we have for a long, long time. Like, since 1968. You think ATF is a bunch of JBTs now? You know how things were before FOPA? How many states had shall issue CCW or reciprocity in the 1980s and 1990s?
The sky is not falling.