Hi Art,
N6812 in the Imperial War Museum is a "Ships Camel" (2F.1), a design for the British Admiralty that differed from the F.1 Camel by featuring a shorter wing span, narrower undercarriage track, revised armament configuration for attacking German airships too, internal air flotation bags, and a detachable hinged rear fuselage for easier stowage aboard Naval vessels. The internal stowage of the flotation bags necessitated the routing of the elevator control cables externally, but this was a specific design feature of the 2F.1 Camel exclusively.
The standard F.1 Sopwith Camels that were deployed for fighting over land featured control cables that were routed internally in the aircraft's fuselage before they exited near the tail end of the fuselage.
As a general suggestion, I would consider getting a Windsock Datafile for the particular aircraft you're skinning (they're very useful for the kind of detailed information you might need on each type, and well worth the purchase price).
In the meantime, here's a link to a good photo album of the very authentic Sopwith Camel replica that flies in New Zealand, and it shows the position of the standard Camel's control cables:
Warbirds Over New Zealand