[Tagging] What is the unit of seamark:light:range?

[Mateusz Konieczny]

What is the unit of seamark:light:range? It is not explicitly defined
at https://wiki.openstreetmap.org/wiki/Seamarks/Lights

http://wiki.openstreetmap.org/wiki/User:NKA/seamark_import mentions
that this import used nautical miles as units, the smae is done at
https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dlighthouse#Navigational_light_properties .

Is it considered as a correct tagging?