First let me say that for a 1896 gun your H&H has remarkably fine breech face--must have been well cared for. The dovetail barrels (in lieu of chopper lump) have the correct 1896 period proof marks, so likely they are original. H&H had only built a factory 2 years earlier in London to begin making most of their guns themselves. The barrels may have come from Birmingham, or even the entire gun. My Birmingham gunmaker friends who apprenticed just after WWII tell me that London barrel makers "could not make dove tail barrels but that Birmingham makers could make chopper lump and dove tail barrels". In the time frame of your H&H, I suspect that London barrel makers could make both style, although I do not know this for a fact.
What I do know by reading old gun catalogues is that the Birmingham A&D gunmakers, who also could make London patter best quality SLE's advertised options of either chopper lump, dove tail and Whitworth steel barrels (as well as damascus) for SLE at the time of the making of your gun.
