I can confirm that the only hinge on the La7 engine cowl was the top one.
The two half cowls were latched together under the engine.
I also note from my pictures of White 77 at kleby that the cannon cover cowl was not hinged either on this ac.(the panel is simply unbolted and removed as one piece) However there are countless line drawings showing just such a hinge down the middle of this panel..
From a maintenance and sealing perspective I would wonder why a hinge was required here. Its a light aluminium panel no more than 2ft wide by 3-4 ft long made rigid by its curved shape and indented cannon bulges.
