It's not normal on a stock car for the idle to wander alot when it's cold, warm, or anytime. It's normal for the idle to be high, but it'll go up to a point, usually between 1500-1800 rpm, stay there, then gradually decrease as the engine gets warm. It shouldn't go up and down repeatedly, not more than 100 rpm's, anyway. It's the part where the idle's goes back to normal when the car's warm that has me confused.
Since my engine rebuild (I/H/C/E, Spoon cams, pistons 12:1cr, tuned), my idle goes way up to around 2300 rpms when I start the car when its cold out, but it holds there, then gradually decreases, a little wandering, but nothing crazy/unusual. When it's warm, idle is normal.