1942 Long Branch No 4 mk 1*/3 barrel ID

[limpetmine]

An FTR is "factory through repair". It is a repair. Not an "upgrade". As in "upgrade in mark", which is what the /3 is. It is the upgrade to the hung trigger from the receiver, as your pictures show. An FTR is parts replacement/wood, but not a change of mark.
FTR's have (usually) the year stamped on it, change of marks don't always have the year.
But some do. Here is an example of this.

If you notice, the crossed flags proof mark has no crown or letters included. Its just crossed flags. One of the inspection marks includes a crown, a Z1 or 21, and the letter E on it's side. I assume that the E is for Enfield, the Z1/21 is the inspector ID, and the version of the crown image consistant with inspection marks from Great Briton.

On the subject of the FTR mark, during my intial search for pictures of /3 versions, the examples I found show a date like 49 and the letters FTR. I admit that I've only been searching for a few days, but i was hoping someone here has exaples of the "/3" mark being the only mark.

So the question here is, did the FTR happen after the /3 conversion, or part of the conversion process?