2. I haven't been able to find the numbers stamped in the wheels, I looked before. The only thing I find stamped on the backs is the capital letter "D". Where should I be looking?
If these are true Mercedes wheels, the numbers are there along with the Mercedes partnumber.
The numbers are cast into the back of the wheels as raised digits, like braille.
A blind person could probably read them,
, the numbers are not stamped into the wheel back... see attached pix
There is no special placement, probably different location on each wheel design. Hard to find sometimes because of the brake dust, but they are there.
In the picture below, the embossed numbers say this example wheel is 7 1/2 inches wide, 17 inches in diameter, and it's Offset is 37 mm.
Probably not for this set of wheels, but good to check anyway, look to make sure ALL four wheels are the same. Sometimes the wheel set is "Staggered", which means the rear wheels are wider and have a different offset than the fronts. This is very important to specify, all 4 the same or staggered, showing the different sizes of the front and rear seperatly.
Don't get upset over the comments, although somewhat sarcastic, the commentors are on the mark, and if you take their advice you'll have a better chance of selling them. Their advice will make you more money!
Besides the basic presentation angle, buyers really can't determine if there are defects below the dirt or not...
You may not have noticed, but the market for good wheels has dropped dramatically, so you need to put your best foot forward to get even close to your asking price.