if you bring anything that required some thinking on your part (like any of the above mentioned gifts), i think they will totally be charmed.
just be yourself, the whole "yes, ma'am/sir" thing always goes a long way. helpin out in the kitchen all that......and i've always seemed to gain points with guy's moms if i can bust on the guy a bit. like, jokingly call him out for something he did that wasn't exactly proper ("i know yo' mama raised you better than that").....depending on how much the mom babies her son, of course, and providing she's not one of those out LOOKING for something wrong with you. my last b/f's mom and me were always crackin on him and it was great.
just have a good time with them and get to know them....the more relaxed you are, the better you will be able to charm them!