Hi mch,
Thanks for posting this information. Have you found anyone that makes a synthetic stock for the Marlin. Your load of 1800 fps with the 405 bullet is awesome on Deer, Bears etc. On this type of game it's more than a light big bore. The Marlin and the 45-70 combo makes the most fun gun I own. Cheap to shoot and still has the big bore kick.
Take good care,
Dave

I just went to the site and checked the pictured part. It definitely looks like one piece and should be easily installed.