I haven't read ACIM so I can't comment on its relevence to perennial philosophy. I can however say that even without ACIM, I think Judaism and Christianity fit very nicely into the "perennial mold".

Heck, "Do unto others" and "Love God, and "Love your neighbors as yourself" sum up in a nutshell the wisdom that is found in any religion or spiritual path that I can think of.
Welcome to the board!