Peter,
I Have never had to tackle this particular job but, having read the manual, I don’t believe it will be too difficult.
If you have not already done so, I recommend you look at Drawing 52 and read through Operation 120, section 16 in the workshop manual.
I recommend you do make the correct un- and re-flaring “sockets” (shown on Dwg 52) and, if you do have access to a suitable press I think you would be wise to make the flaring tool MR3445-4. That said the manual does state “failing a sufficiently powerful press, the operation can be undertaken with a punch and hammer”.
The two sockets will ensure the old stud is unflared and driven out and the new inserted and flared with minimum risk of damage to the drum.
The “indent” that you refer to should be a dowel pin which I would expect can be driven out with the old stud. Once the new stud has been fitted a new dowel hole should be drilled away from the position of the original and a new dowel inserted as per the book.
Good luck!
B……………..