That would not be legal here in Maine, unless you agreed to buying by weight up front.
From Maine statutes:
§2302. Definitions
As used in this chapter, unless the context otherwise indicates, the following words and phrases shall have the following meanings: [PL 1973, c. 91, §1 (RPR).]
1. Cord;
A. A standard cord is a unit of measure of wood products 4 feet wide, 4 feet high and 8 feet long, or its equivalent, containing 128 cubic feet when the wood is ranked and well stowed. Any voids that will accommodate a stick, log or bolt of average dimensions to those in that pile shall be deducted from the measured volume. [PL 1979, c. 659, §1 (RPR).]
A-1. A cord when used in connection with sawdust, chips or shavings means the volume of material contained in 128 cubic feet at the time of sale. [PL 1979, c. 659, §2 (NEW).]
A-2. Fuel wood, when sold loose and not ranked and well stowed, shall be sold by the cubic foot or loose cord, unless other arrangements are made between the buyer and seller. When sold by the loose cord, the wood in any cord shall average either 12 inches, 16 inches or 24 inches in length. When so sold, the volume of the cords shall be: A cord of 12 or 16 inches in length shall mean the amount of wood, bark and air contained in a space of 180 cubic feet; and a cord of wood 24 inches in length shall mean the amount of wood, bark and air contained in a space of 195 cubic feet. [PL 1981, c. 219 (AMD).]
B. A face cord is a unit of measure 4 feet high and 8 feet long, or its equivalent, containing 32 square feet. The length of sticks shall be agreed upon by both parties; [PL 1973, c. 91, §1 (RPR).]