the old MXR's are either BUD or Hammond depending on when it was made. but from a functionality standpoint i think the current Hammond will fit either. but i'm sure you'll have to buy the whole box just to get the cover. Although, the Z Vex one that has the power supply connection will work also. and is available separately. plus you get a power supply connnection. that's what i've got on mine.
Too busy chasing babies around the house to get to play guitar very often.