I was going to do that with a 336 I was rehabbing for a friend, but when the pachmayar pad was added, whomever did it removed about 7/8" off the stock to retain the LOP. It would have been easy enough to sand down the circumference of the new butt-plate but then would have had a 12 3/4" LOP. Make sure it hasn't been cut at all.
John