I am not absolutely certain, but I am pretty certain that the fabricated rear sights were designed, produced, & fitted during WW2. They were a cheaper & not so nice alternative to the Mk1 'Singer' sight, but a rather better proposition than the crude Mk2 'battle' sight. I daresay that all the information is quoted chapter & verse in the LES.
If the rifle is really unadulterated & not FTR'ed & it bears a rear sight marked up to BSA then there is a good chance that it is a rifle produced by BSA at their Shirley factory near Birmingham, UK. The regional factory codes were applied to parts for some years after the end of the war by some manufacturers, BSA included. I've seen woodwork marked M47/C & dated in the mid-1950's. The secret factory codes were allocated sequentially, & began with either a 'S', a 'M' or a 'N', for Southern area (Southern part of
England
), the Midlands (which allso included Wales IIRC), or the North of England & Scotland. So, BSA, being based in the Birmingham area of the Midlands of England, was given a 'M' prefix, & just happened to be manufacturer number 47 in the Midlands area. The addition of the 'A', 'B', 'C', or 'D' simply indicated which of the four BSA facilities made the weapon/component. When the codes were adopted by BSA in 1943, at least initially, the last letter was not applied, so seeing rifles & components just marked 'M47' is quite common.
Hope this helps a little.
As ever, if the OP can get us a few photo's of the rifle in question he will no doubt get plenty of helpful advice - unless the rifle body has been linished, the manufacturer's name or code is likely to be on it somewhere, along with the year of manufacture.
PM
Originally Posted by 
