Help with markings No 4 Mk I

[RobD]

Surpmil, here are more pics of that front scope mount - does it look OK now? Can anyone explain some anomalies with this rifle (clearly what I am dreading is that this rifle was put together as a 4(T) by a civilian):
1. for a BSA it does not have the M47C on the buttstock ring (though it does on the trigger guard).
2. The number Y4515 is on the bolt, forestock, electropencilled on receiver and on wrist beneath the butt socket - yet the main serial number on the butt socket (see pics earlier on this thread) really does look like Y1515 not a mis-stamped Y4515?
3. Is it wrong for a 4(T) to have the forestock numbered across the wood and not down it?
4. Is it wrong for a 4(T) to have a short butt? The rifle comes in its transit case, the case is legit, so the rifle is half an inch short for the box, because of the butt.
Thanks for all the thoughtful posts.
Rob