Mike,
In looking at the write-up on this piece in GBG 1540-1740, Neal lists the gun as "unsigned".
He also states that the monster side-plate is "restored" as well as stating the lock, although from the same period as the gun is a "replacement".
By delving into his writing over the past few years, I believe the restoration of the plate and the replacement of the lock was carried out by Neal himself , therefore there would be no need to explain why he thought the lock was a replacement.
He had acquired this gun in the first quarter of the 20th century. He had it on exhibit at The British Sporting Exhibition at the Imperial Institute, South Kensington, in 1938.
I will email some other info.
James
