I believe the blade is a replacement.
It was purchased as a Randall trench knife, and is supposedly one of only 3 known to have been made by Randall.
One is in the Randall museum (I am told), one is (or was recently) in the possession of one of Tom Clintons sons, and this is the only other one I have seen or know of.
I know the blade to be original and my main concern was that the L F & C handle is also an original piece.
I am sure of the date of marrying the two up by Randall but am comfortable in the belief that it is an authentic Randall trench knife.
If you Google Randle knife history there is a picture of the knife in the Randle museum the blade is a different shape and the markings do not look the same and your knife looks to have a mint blade better than Randle's museum knife.
If you can post a link to where you have seen the picture I would appreciate it, as I have watched some of the videos of the museum but can't see a link on the Randall site.
In one of the vies there is a fleeting glance of the hilt, but that is all.
Randall do many blade styles and this is a model 2 7" blade.
I know of one more model 2 and also a model 1 but am not sure which is in the museum.
This blade is far from mint and has been authenticated by a coupe of experts as an early Randall blade.