I guess if you really like the bag and understand the material you’re getting, it’d be an easier choice for you.
Keep it if: you bought the bag for what it is and as it is, (aged calfskin) able to withstand day to day use, it’s not hardy as caviar, but it is lighter and creases seem to give the bag more character.
Return it if: you can’t swallow paying X amount for a bag that you don’t absolutely LOVE. If there was a popped stitch out of the box or defect in workmanship. If you already paid X amount what’s X + 300 more, for something you’d love and give you peace of mind.
I personally think that if the your specific bag: I love the color of the bag and hardware, I understand the aged calfskin leather and characteristics, what makes a 2.55 bag a 2.55 (the chain and M-Lock), current creasing you’ve pointed out; I would keep it and if I don’t keep it, pay the 300 or more for something that I can live with (maybe a different type of leather, different hardware or leather color, one with more/less creases).
It’s really a chard choice, I understand.
But break it down to:
will I love this piece?
will I use this piece?
is it worth $3500 (or whatever your X amount was) perfect (to you)?