How to know if a PS3 rom is updated?

Rpcs3 is each day better and more games are playable.
Different from PS2 and and old consoles, since PS3 the developers release update patches that fix bugs of the original release. The new games are more buggy because the developers know that they can release patches.
Therefore I have to download a rom that includes the bug fixes.
Then, how do I know if a rom is patched? Do I have to download the patch separately?

I don't know anything about rpcs3, but for PS3 game updates you can check to see if there are updates and/or DLC for a title ID on Sony servers.
Been some time since I messed around with these games (for OFW injection and also CFW) but think you use PSNStuff+ on a PC to check for updates etc.
Some titles will have multiple updates.

I don't know if your emulator has some method of applying updates like a real PS3.

Of course some releases will have most if not all updates already applied, eg Oblivion GotY & Skyrim Legendary Edition (but idk why anyone would want to emulate those particular titles, they're on PC anyway).