Are you absolutely SURE about this 2BA mouthpiece screw assertation Lester? There MUST be a mistake............. I have probaly fitted several hundred + new mouthpieces to No5 scabbards over my years as an Armourer and it's a 6BA machine head screw. A 6BA screw will drop straight through a 2BA tapping size hole - yes?
Regarding the Indian No5 bayonets, those made for the Indian Army Sterling SMG's (and long and short L1A1's) are made from (virtually) identical steel spec as those made here. Just touch one on a grinder or subject one to a DPN test to see what I mean) I can't comment on the 'tourist' trade but certainly can vouch for the Army ones. Can you imagine Indian Army soldiers being given low carbon mild steel bayonets while fighting in the NorthWest of the Country............., they'd be a laughing stock. They're a bit rough and ready but to be honest, you can say the same about the dismal uinfinished guilloutined edges of Hopkinsons L1A1 efforts