No, you can't tell with FB. Marcia de-friended me as I expected and good riddance.
The other is a mystery. Although I've noticed this number can fluctuate by one or two at any given time. I don't think it is ever 100% accurate.
There is this one evangelical Christian from high school (he was Methodist then) who alternately friends and de-friends with regularity; I just go with his flow; he rarely posts. I seriously think I offend him, then he returns to try to save me, rinse and repeat. It is pretty sad because he is one of the most isolated, lonely people I can think of - and also as deep in The Closet as one can be with the door shut and locked. :/