Idel problem???

Whats our avg. idel rpm of our cars....namely an SL? I was driving today and I noticed that in traffic when I would put the car in neutral the rpms would read at about 1500 rpms. Also, when I was cruising I just put the car in neutral and then the rpms dropped to 2k, stopped, then shortly after dropped to about 1500 rpm. I might be imagining things but I dont ever remeber my car doing that when I put it in neutral while the car was moving, usually it goes staright to about 1200k rpm if I remebr correctly. The weird thing was, when I got home and as soon as I did, I restarted the car and then the idel read 1k-800 rpms, which I believe is about normal. So is there anything I should be worried about, maybe I need a new clutch? Thanks

Clutch has nothing to do with idle. Your IAC may be dirty and/or your BISS needs adjusted/

So all in all, it's nothing too serious from the sound of things?