Hi,
They would be let out from the hem. These have cuffs, I would unroll the cuffs and measure the amount of material on the inside of the unrolled cuff to the stitching. Tell the buyer that there is 1 and 1/2 or 2 inches ( whatever the actual measurement is) of available material to be let out. But remind them that not all of that material is useable, there has to be some kind of a hem. Hope this helps.