Source for pics on Whitneys
Consider obtaining a copy of "The US Model 1861 Springfield Rifle Musket" by Hartzler, Yantz and Whisker. Toward the back of this book, you will find clear pics of various Whitney Model muskets including the 'Manton' marked rifle-musket.
I purchased mine sometime back from Dixie Gun Works when I was doing my contract "1862 Bridesburg" riflemusket project. I highly recommend it.
It was just before dawn, One miserable morning in black forty four.When the forward commander, Was told to sit tight, When he asked that his men be withdrawn. And the Generals gave thanks, As the other ranks held back, the enemy tanks for a while. And the Anzio bridgehead, Was held for the price, of a few hundred ordinary lives. "When the Tigers Broke Free" by Roger Waters