The Messiah and patches?

[Karrade]

I've run a search on patches and read through a few threads, but I was never one to be able to comprehend writen directions well. On a couple posts, "patches" are only extras and never needed? I have an old PSX with MOD chip and just got PS2 and since the messiah seems to be the chip to get, I'll aim for that, but with PS1 games needed patches to run. (i.e. Dino Crisis)
Are any of the PS2 games coded like Dino Crisis was for PS1, and if so, messiah already takes care of it?
Plus, since PS2 does support the PS1 games to an extent, messiah work those back-ups too even when they're patched themself.