Imagine you are your mom, and you are helping with your daughter and your new grandchild.
You are delighted that you are physically able to help, you are delighted that your grandchild is healthy, you are delighted that you daughter is healthy, you are delighted that you have a good relationship with your daughter and son and law where you are welcome in their home, you are delighted that they take your offer of help and your actual help as, well, help, rather than an attempt to control.
You would want to be acknowledged for your help, that it is wonderful, that is not an entitlement. You don't want to feel like you are being paid for what you are doing out of love.
So I agree with giving her things that are grandmotherly....some time playing with the baby that isn't work time, a picture with the baby, and her overhearing you tell people what a great help she was!