If you turn the 1200 upside down you'll see the accelerator "hatch" in the body. Sometimes the cover is missing, sometimes in order to add extra ventilation for an accelerator. Anyway, if there's a just a connector and some space there you have no accelerator, but on the other hand.... :-)
The other thing is you might have just a memory card there, but this actually doubles the speed of a lot of operations so is a lot better than nothing.
If there is nothing there and you don't think you'll upgrade the 1200 then find a utility called Relokick 1.3 or 1.4 or whatever. It can work from a floppy and provides very good compatibility with those old 500 games. Probably best though is an 030 accelerator (Blizzards are ideal) with a few megs of fast ram, a hard drive, and installing the wonderful WHDLoad.
Hope that helps.
