That's not an icon.
Anyway, from what I can tell, there was no real reason for you to create another thread. If no one replied, just wait patiently alright? Since you're new, let me teach you about forum etiquette, don't go around posting multiple times asking about the same thing. Just wait for people to reply :3
Anyhow, I've merged your threads :3
Back to the question, yeah, you can edit your Mystery Gift Block, and remove the data via hex editing.
The question is: why? There is no real need to do that. What is your purpose for wanting it deleted?
Bringing this up just in case you had these thoughts:
1) You can receive another Poke Ball Mew, even if the record still shows in the gift album, as long as you buy another Poke Ball Plus. Explanation: This gift is set to be multi-receivable. For every ball you purchase, you can redeem another Mew from it.
2) Deleting the record won't allow you to receive another Poke Ball Mew from the same Poke Ball Plus you used to redeem this Mew. Explanation: think of the redemption as a one time serial code; the serial code was used when you redeemed it the first time round.
Since it's a one time serial code, you cannot reuse it once it is used.