When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The location that Joe showed is correct, but you might have a little trouble reading the numbers depending upon how rusty your frame is and what POs did. Mine took quite a bit of careful cleaning and some enhancement of the image with Photoshop.