No, there's not. The M24 action is only 3/8" longer than the M20, and the part of the stock that's lengthened is through the magazine area--where there's slightly more "cut-out" for the longer magazine.
I've weighed a bunch of Model 20, 24 and 28 NULA stocks, and they vary more due to the fact that they're individually made than the action length. And that's rarely more than an ounce or two--which can be due to the particular paint used.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
