I wouldnt ask either, but it would bug me wondering to haha.
If she said to you " we gave it away" what would you say to her? would it make you angry? Im not sure if its worth knowing
I will be peeved but more because I know how MIL is with returning presents and how she knows she could have told me she did not want them or wanted a different type, she has done it before with no dramas. In fact I am fully expecting her to want to change the top I picked as her mothers day present and I am fine with that because I would rather her be happy then have something she does not want.

I am probably going to go against the grain and I will say something. MIL and I have a great relationship and I know this will be something (I know, very minor) that will continue to play on my mind.

Thanks everyone for your opinions though.