The 42 series also has Bayonet lugs mounted underneath as does the 1812 series so the bayonets would have been made to fit with the blade on the right side not the left. The 1808 contract muskets were really nothing more than 1795 muskets made by private makers. The contacts specified that they be copied from pattern pieces supplied by either Springfield or Harpers ferry. So if they received a pattern piece that had the bayonet lug mounted on the bottom of the barrel that is how they made them. The Bayo lug was moved to the top of the barrel during the life of the 1795. Hope this helps. 1795 muskets can be found with either configuration. Remember each musket came with its own hand fitted bayonet because each musket was hand made and tolerances were allowed so in reality if you ever see an American socket Bayo mounted where the blade is to the left of the muzzle it is not a correct bayonet for that musket.
Mack
hitler, stalin and mao were progressives in their time