What do you mean useless?
nameplate1 is a valid unitid like
target or
player.
You can compare units with UnitIsUnit or by using GetNamePlateForUnit.
http://wowprogramming.com/docs/api/UnitIsUnit
local isSame = UnitIsUnit(unitId1, unitId2)
local nameplate = C_NamePlate.GetNamePlateForUnit(unitId)
|
Last but not least you can snapshot certain guids and match them against nameplate guids.
http://wowprogramming.com/docs/api/UnitGUID