gun guy there thinks it is a replica because the wood is not hardwood
Amusingly, unless it isn't made to be fired, it'd still be considered an antique. Reason being that flintlock rifles (not pistols) fall under some specific category... archaic or some word starting with a P comes to mind. Anyways, flintlock rifles (and matchlocks) aren't considered firearms unless used in crimes, unlike all other firearms. Therefore, unless the gun in question is made without a bored out barrel, or is very very very clearly not meant to be fired, it's basically an antique.
Also, to further cloud the issue many modern made middle and low end flintlocks are shipped to the buyer without the vent being drilled, because of the laws in the country where the gun was produced place extra restrictions on fully functional guns. In Canada however, they're still considered flintlocks and not replicas, because we can't have replicas, but can have flintlocks.... welcome to the gongshow.\\
P.S. The police are not known to be knowledgeable on guns... even modern ones, and even specialists. His statement on it not being hardwood could be correct... except that it could be a rebuilt gun using original parts and a reproduction stock, so he'd need to check the stamps... and I know nothing of these guns or the wood that's currently on it... who knows if he even knows what wood is on it, or if light coloured hardwoods were used when it was made, or it was refinished....
basically, get pictures from your friend, detailed well lit pictures of the whole gun and of any particular markings on the lock, butt, butt plate or around the breech of the barrel, then post them on here and people will be able to tell exactly what it is. Failing that, get her to take some very detailed notes of what she sees. The devil is in the details on old guns.