Yes — an older manual-focus lens with an aperture ring is often a good choice for reverse macro, because you can set the f-stop directly after the lens is reversed. In general, the shorter the focal length, the greater the magnification when reversed.

You can reverse-mount lenses from many different systems, not just Canon EF, as long as you use the correct reversing ring for that lens’s front filter thread and your camera mount. The key point is that reversing rings are sized by the lens’s filter thread diameter, and those sizes are not all the same, so check the specific lens before buying.

An older FD or other manual lens can work fine for reverse macro, especially if it has a manual aperture ring. Just make sure the ring matches both your Canon EF mount and the lens’s filter thread size.