Help ID gun show find?

[Bigmon]

My cousin bought this a show today. Pretty sure it is an original English percussion fowler / shotgun?  But really not how old.
There is a poor hammer screw replacement and the butt plate is just so simple, could it be right?
But it is in nice condition otherwise.  The barrel is about 20 ga, has the proof marks,etc.
There is what looks like hand engraving, three or four words we can't make out except the last looks like "London"??
Also it looks like "London" on the lock plate
Any help would be appreciated in ID'ing this thing. I can ad a few more pics but not all at once.
Thanks

[Bigmon]

Wow, no one yet commented. I don't think this is a newer made gun.  There was a knowledgable man there that took a look and thought it to be CW era?

[rich pierce]

Is there a clock ticking somewhere? 

The lock is a later flintlock lock that has been converted to percussion. Gun may be restocked, or cut to half-stock when converted. Lots of refinishing.

[Brent English]

I agree it's a 20th century restock of older parts. Looks like the stock is black walnut.  A new breechplug tang was probably added during the reststock.  The barrel and lock may have started life together.  Hard to say exactly when, but I think those proofs are post-1813 if I remember right.  Converted from flint sometime in its working lifetime, probably long before the restock.  If the bore is good, it will make a nice shooter. 

[Bigmon]

Thanks you all for the knowledge.  I don't know why I didn't realize that had been a flintlock?  Just stupid I guess.
The bore is decent.  Not shiny, but not rusted or pitted.
I am going to replace that hammer screw for him.  That should make it look some better.
It has a neat feature on the rent of the RR, not shown.  There is a jag that stays on it but then reversed when needed.  I'll take a photo when he brings it back out.  I had not seen that before that I remember.
I appreciate you opinions.  That makes all the sense in the world about being a re-stock.  It is very plain but cleanly and neatly done.
Rich Rosenburg was at the show and he estimated pre CW, but didn't mention anything else. He is big into longrifles and this was probably way too plain for him.
But we like it.
Regards to all