Isn't legality based on visibility?
The 501 series light is visible for 1 nm, the 601 for 2 nm. Canadian ColRegs require a masthead light to be visible for 2 miles on a vessel less than 12 metres in length so the 601 could be used.The mooring reference is interesting. It is my understanding that if anchored in a designated anchorage i.e. a mooring field, an anchor light is not required.