And just to get this out of the way, the carry flag’s behavior after multiplication isn’t an important detail to emulate at all. Software doesn’t rely on it.
On as fixed of a hardware as a game console, and with the accompanying anti-piracy/anti-cheating/emulation efforts of that industry, I'd expect it to be. From the history of emulating previous consoles, we know that any deterministic difference can and will be exploited, either to determine whether the hardware is authentic, or incidentally as a result of unintentional bugs.
On as fixed of a hardware as a game console, and with the accompanying anti-piracy/anti-cheating/emulation efforts of that industry, I'd expect it to be. From the history of emulating previous consoles, we know that any deterministic difference can and will be exploited, either to determine whether the hardware is authentic, or incidentally as a result of unintentional bugs.
This reminds me of the Z80, where two undefined flags resisted analysis for several decades; a 2-year-old set of slides on the state of that here: https://archive.fosdem.org/2022/schedule/event/z80/attachmen...