This is the first Amiga 1200 we've ever had. Always had 500s and 600s.
First time I'm getting to experience the AGA chipset.
I can't remember the name of the disk, but I had one that would allow your 1200 to boot as a 500 for compatibility with older games. Every time it loaded, you get the red error screen, but a quick soft reset would allow it to boot into 500 mode.