Mrs BTB reckons Heckklappe for a bootlid (saloon), and Hecktüre for tailgate (estate). She's only a girlie, mind ...
She says Rohbau is something like skin or shell (depending on context).
That's what EPC translates it as. The literal translation of the EPC section Back wall door
Hecktüre sounds more everyday use though
No it doesn't, Rohbau means shell, ie the bare panel without locks, glass etc.
Heckklappe is a tail gate, Hecktüre is more likely to be used for a rear door as fitted to a van. You also occasionally see kofferraumklappe.