

Like I mentioned above, I had acquired this lock from JD Beck, or Beck's Flintlocks who already had remodified this Dale Johnson lock.
The key differences was
1. The finial on the frizzen spring, that either was reforged or added to the spring.
2. The sear spring screw hole was concealed.
3. Although barely noticable, The tail end of the lock was slightly reshaped.
Since the making of this rifle, and at the Kempton Gunmakers Fair this year, I noticed that Barbie Chambers actually came out with a secondary Dale Johnson lock that has a blind sear screw hole.
You still have the option to buy one with the 2 screws showing, or buy one now with the one screw.
I had used Dale Johnson Lock on other builds as well, where the modification was even more noticeable.
For example here is one I did for a Jacob Dickert Lock.

On this particular Lock what I remodified was
1. The plate was thick enough that I removed the little moulding slashes, that gives it more of a flat plate appearance, and then I reshaped the bevel on the outside of the lock.
2. I created a blind hole for sear spring screw.
3. I reshaped the pan bridle.
I did not reshape the finial of the frizzen spring on this particular lock. One thing I noticed on different pictures it seems like the frizzen spring finial are not always the same on the Dale Johnson locks.
The first photo which I got off the Internet you'll notice the spring is different from the last photo that I put on, and they were both The Dale Johnson locks.
Hope this answers your question.