Yes,
Just like single malt said. Acer did a tutorial on piece by piece lock inlet in the tutorial section. Unfortunately, the photos are held hostage by photobucket. There is a temporary fix that you can do so that you can see the photos. Look in the over the back fence section. there is a thread about fixing the photo bucket thing.
Acer's tutorial would be a good thing to look at for your first lock inlet. If you can't see the photos, then certainly reference a good building book.
As single malt said, start with the bolster and lock plate using chisels. Once you get that in just as you want it, pencil in all the screw holes and the cock hole, through the lock onto the background. That will tell you where most of the lock internals go. You can then trace the pattern of the lock internals and use a drill bit or forstner bit to take out wood. Don't take too much!
Cheers,
Norm