If the day regularly designated for the delivery of benefit checks under subchapter II, VIII, or XVI falls on a Saturday, Sunday, or legal public holiday (as defined in section 6103 of title 5) in any month, the benefit checks which would otherwise be delivered on such day shall be mailed for delivery on the first day preceding such day which is not a Saturday, Sunday, or legal public holiday (as so defined), without regard to whether the delivery of such checks would as a result have to be made before the end of the month for which such checks are issued.