Bob's lock is of the Alex Henry style for use with an 1-1/8" barrel. The Davis drip bar will combine with it, but won't work with a 1" barrel. The L&R drip bar will work with a 1" barrel, but not with Bob's lock.
The reason is available breech plugs. There is a section cast into the breech plug that denotes the location of the upper part of the lock panel for proper architecture. Using an Alex Henry style lock will place that line too high up on the stock. English components work together as a set, ie the breech, tang, lock, trigger plate and trigger guard all locate each other. There is a screw that goes thru the trigger plate into the standing breech. There is a screw that goes thru the tang into a boss on the trigger plate. These properly locate the trigger to work with the lock. I haven't found any combination of random parts that will work together.
The top rifle has a 1" barrel and uses components from Pecatonica's Rigby rifle, but uses an L&R lock and their drip bar.
The bottom rifle has a 1-1/8" barrel and uses Don Brown components with a Roller lock and Davis drip bar.
Building one of these is a complex build with the proper matching of components being critical unless you are a whiz-bang machinist and can make some of them.
