Do you actually want a 4th FD body? And who's to say it wouldn't need a cla, maybe not right away but sooner then you would want. I'd say look at your film consumption and base your decision on that. 1 roll a month, don't buy anything. 2 rolls a month keep your camera in good condition. 3 rolls a month, get a body you've always longed for.
I've found that cameras are like cats. You can wind up with too many too fast and they seem to never go away.