It is certainly valid to take a literal interpretation of the prototype and depict to the point that it was historically completed, that is, with no armament, or in some other state of half completion. but I would not object to extrapolating a bit to say 'this is what she would have looked like if completed". Case in point is the TA183 being built by mike wint , this aircraft was never actually built, but it is quite okay to build in a what it might have looked like configuration. .