Interesting, you have seen way more 4T's than I but I have not seen one with a Mazak butt plate - maybe they have all been 'messed with'.
Did H&H remove the BSA butt plate and replace it with a Mazak one, or did BSA change all of the T-rifles with one before despatch to H&H.
Where did H&H or BSA get the Mazak ones from ?
When PL viewed mine he did 'sign it off' as all original and didn't make any suggestion that it had the incorrect butt-plate - have I been conned ?