I am not sure if these pouch’s were ever confirmed to be original USMC Issue.
The original consensus years back when they hit the market in great numbers, was that they were original TSMG R.M.CO 1942 Pouches, that were released from Russian Lend Lease Surplus and had the USMC Markings later added by an unscrupulous dealer. Keeping that in mind, I personally would not value it at any more than any other WW2 Pouch.