Another vote for caviar (purely because of durability) and gold hardware. Either black, white or beige clair caviar M/L with gold hardware is simply STUNNING!!
I would choose lambskin if the lambskin is anything like the vintage flap but too bad it isn't.
Since the M/L is a smaller bag, it is more suitable for evening use and I personally think gold hardware will stand out better than silver in the evening.
But whatever it is you choose for her, I know she will be happy! She can also exchange it to other color combination if she wants to with the gift receipt.
It is truly thoughtful of you and she is lucky to have a friend like you.
I would choose lambskin if the lambskin is anything like the vintage flap but too bad it isn't.
Since the M/L is a smaller bag, it is more suitable for evening use and I personally think gold hardware will stand out better than silver in the evening.
But whatever it is you choose for her, I know she will be happy! She can also exchange it to other color combination if she wants to with the gift receipt.
It is truly thoughtful of you and she is lucky to have a friend like you.