It does. An anchor light is a 360 degree white light hoisted in the rigging. An aircraft, like all vessels, anchored in a navigable body of water has to have an anchor light dusk to dawn, unless in a designated anchorage area (usually a field of mooring balls). Vessel, including seaplanes, have sometimes arcane responsibilities under maritime law that greatly affect insurance & liability when ignored.
I remember an unlit sailboat anchored at the edge of the Intrecoastal Waterway back in our cruising days. When the tide changed, the sailboat drifted into the ICW & was mashed into the bottom of the ICW by a tug & barge, drowning the family on the sailboat. No fault on the tug skipper.
of course, seaplanes, being shallow draft, tend to anchor in very shallow water. But close to shore is where skiffs, jetskis (jetsperm) & other penis extenders operate at high speed, often by drivers in a high states of inebriation. Under maritime law, near absolute liability attached to the question of whether the vessel struck was lit by an anchor light at night.
so anchor lights are important. Until now, however, I’ve never wondered if seaplanes like the Lake LA4 come with anchor lights.