Shine some light on this Heavy barrel No.1 for me.

[jonh172]

Thanks Cinders!

Bottom of sight leaf has WA 43 = "WA Wellington Annexe" and 43 is when the leaf was made?
Stock has MA 3/'47 = "MA xx (year) Rebuild at LSAF"
So this one was rebuilt at LSAF in March '47.

Would this barrel have been installed then? Or is the '44 on the barrel the install date?

Is it common to have a mismatch bolt during a rebuild?