Something lost in the translation?
It's hard to dispute Boudriot... but the English definition of Tartan (or Tartane) is very specific in a variety of sources (Steel, Oxford Guide, Sea of Words) as a small (at 1/150th scale, the Heller model scales out at 100 tons - large for a 'small' vessel), single masted (Heller model has two) coastal vessel with a staysail (as does the Heller model). Illustrations accompanying the definitions show a simple plan with relatively flat sheer and simple stern since there is no mizzen (the Heller model has a distincitve sheer line and the raised poop extending well aft of the rudder post as shown in illustrations of xebecs).
But Falconer lists a Xebec as having three masts (as mentioned in my first post). It doesn't include a reference to tartanes.
So it appears that from an English point of view, the vessel may be neither tartane or xebec, but either a hybrid (large tartane or small xebec?) or apocryphal (there are other models in Musee de Marine that are flights of fancy - frigate La Flore for example and then there is the "Le Gladiateur" kit from Heller).
Of course, the last time I looked, England was not a Mediterranean country, and it had its own linguistic problems distinguishing between a 'sloop' with one mast an a 'sloop' with three.
So back to your original question, is the model straight out of the box representative? It appears so, you just need to figure out what to call it... maybe it's a Corsair.