No, I won't say it's a fake. It's genuinely put together from parts, a fairly genuine-looking lock with a barrel decorated by Ali Baba personally and a hand-carved trigger guard. All fitted to a doubtful piece of wood with a definitely home-brew pistol butt plate and ring. There are plenty of this type being offered on that online-auction site. And most of them are in the category "Khyber Pass Specials". The trouble with photographic evaluation is that many of them incorporate original parts as well as bits hammered out in the back yard.
I know it's hard to be disappointed again. But I also know what's on offer here in Germanypretty well. From my own experience, do not buy anything unless it is a) at a wallhanger price, or b) it is from a dealer who guarantees to take the gun back if it turns out to be fake.
In your first post, you wrote
If that includes your father, as the intended recipient of the present, are you sure that it is a wise idea to spend a lot of money on a supposedly genuine original, with the real risk of being fooled by a plausible-looking fake? There are a lot of good replicas around.
P.S: I just had a look at the complete set of photos in the online auction. It is clearly a (the word you don't want to hear) built round a plausibly original-looking lock.