Not sure why I didn't get notified of the two responses. But thanks for the contact. I went slow and it wasn't difficult. Pretty simple mechanism. I left the lock as I found it minus the grease and dirt. As previously indicated, the lock functions perfectly and the flash hole is clear. I still need to remove the damaged nipple though.
As far as cleaning the most abrasive thing I used was a paper towel wet withpenetrating oil. Picked up as much dirt as I could without being aggressive. The barrel will need to be checked out by a gunsmith. After initial cleaning I find that all but the last 6" on the muzzle end is pretty clean and pit free. The last 6 or 7 inches has three pitted areas. What I can't tell is if the pits are in the barrel itself or if they are in lead deposits. With a small light located at the breach (.69 caliber can fit a decent sized mini light) the pits look large (cast a decent shadow) but as you move the light closer to the pitted area the shadow from the pits disappear and I can't actually see the pits. And the area the pits are located in is shinier than the rest of the barrel. Hopefully the gunsmith will have more experience in making that determination. One advantage of the 1842 was the barrel was formed 'thicker' in anticipation that rifling could be added later. If the pitting is in the barrel steel maybe this added thickness will help.
If the smith determines that the barrel is unsafe to shoot I am considering a replacement barrel to shoot while keeping the original barrel for display. It would be another $350 but the wife got a pretty good deal on the musket.
I did find some numbers on the backside of the lock plate, under the trigger guard plate and on the bottom side of the barrel but cannot find the numbers on the left side of the barrel. The area where the serial number and proof marks should be appears to be 'distressed'. Either by small hammer blows or more likely being in a vise without padding. I can barely make out the 'V' but can't see the P proof mark. The area where the serial number should be looks almost intentionally distressed with small hammer blows. I don't think that the numbers will ever be visible and I wasn't going to take the chance of removing the patina to try any harder. The area of the stock that should contain the cartouche(s) is pretty clean but no sign of a cartouche. Maybe it was a replacement stock or sanded at some point in time. I have no plans to alter the stock as it looks just fine as is. It matches the patina on the metal. I still think it is pretty neat item. This is my first black powder firearm.
I'll post pictures tomorrow. My 13 year old daughter is in charge of photographs and I have to line her out. I have actually 'commissioned' her to photograph all of my firearms this summer.