I just called the woman at the company. She said I should get a replacement kit at no extra charge. I don't have to return the defective kit I have now.
I made this 4-star review at amazon.com as follows:
"I received the box with 10 gray sanding cloths. They were all the same. No clear identification as to what grit level they were. I called Lila (Hercules Distributing of West Allis, Wisconsin) at the number printed on the instructions. She said I will receive a whole new kit with the sanding sheets clearly labeled on the back this time. The instructions said there were supposed to be some numbers on the back of the sheets indicating the grit level. There's just some other numbers that look like a part number or something. All the print on the backs of the cloths look the same and some of print looks like it's cropped off."
Current Model Worked On; 1/25 AMT Kenworth W-925 Tractor Kit, Future Models; 1/25 AMT Wilson Cattle Trailer, 1/96 Atlantis Boeing 727, 1/48 AMT Bell 205 Helicopter