I remember this and you're right, why wouldn't she do that to honor Matt's mom? They could have both had yellow ones. I'm very sentimental about things like that and probably had them put "For Mom" for the engraving on the back too, so I understand what you're saying.
I was actually pissed that she went and got another pink one, as she already had it and why not pick up another color to match your outfits better? They all work the same so you can interchange them, even ones from years ago. I bring all mine when I go just in case