Whether or not any order is "really" legislation from the Executive branch is a matter of opinion and interpretation, just as it is a matter of opinion and interpretation as to whether court rulings are "really" legislation. There is an essential difference between legislation and other forms of law-making, that regulations must be under specific authorization by act of Congress. So the immigration ban pointed to specific authorizing legislation passed by Congress, and any specific regulations that emerge from that order will likewise refer to particular authority. Any dictate that exceeds that authority may be overturned by court (or not... judicial interpretation is optional).
However: there is no quantifiable unit "regulation". Actually, they are called rules. So there can be no "two for one" regulation.
For reference, here is the text of the order. It defines "regulation" as
an agency statement of general or particular applicability and future effect designed to implement, interpret, or prescribe law or policy or to describe the procedure or practice requirements of an agency...
Perhaps this refers to a docket number published in the Federal Register. Also note that the actual order requires identifying two regulations for each one added -- not eliminating, just naming.