Guns with sideplates that serve no purpose other than stying or decoration are not as uncommon as one would expect.
Decorative sideplates attached to boxlocks are well-known and have been widely used for a hundred years or more.
I have seen Dickson 'round action' trigger plate guns with decorative sideplates and the whole action made up to resemble a 'London type ' sidelock from the outside.
A lot of early 'transitional' hammerless guns from the 1870s and 1880s have side panels, some carry the lockwork and some do not.
The locks have to be mounted somewhere - they will be mounted either on the top strap (like the T.Woodward 1876 patent with spiral springs) or on the trigger plate (like the MacNaughton 1879 patent), on the lock plates, like all sidelocks or inside the action body, like the 1875 Anson & Deelry patent).
Clearly, only if the lock work is actually mounted on the lock plate is it a 'sidelock'.
It was not at all uncommon for gunmakers to work towards an external aesthetic which was the preferred 'mode' of the day, despite the internals being quite different. Note that the Akrill has bar-lock style lockplates but is a back-action. Quite different from, say, a Holland and Holland 'Dominion'.
