Given the differences in size and curvature you describe, it might be useful to have a view of those two in profile - any chance?
The genuine top looks to have the same profile as a KL80 smoke deflector. I wonder if they used the same former to spin them. As far as the reproductions are concerned, if you're going to go the extent of having a new former made to re-manufacture them, wouldn't it be far more sense to have it made to the original i.e. correct profile than something that's not even close? Or is it just me? At least it makes our task easier to spot them, I suppose...
The black hood in question was never listed as a SDR hood. This was advertised as a X246 Hood which was originaly in orange. The reaason they were made in black is because at the time orange enamell was a specialist colour, however they are now in orange. I have no idea were anybody got the idea that these were a repro of a SDR hood.
Well, they're not a fair reproduction of the X246 hood either because that's the same profile as the SDR hood, IIRC (and not having one to hand at 2.15am). Tilley never made a hood with the same profile as that reproduction, whatever lamp or lantern you say it was intended for. Nighty-night...
As mentioned by Tony earlier, have a look at the Korean eBayer kkn4602. I have one of his and its profile is a lot closer to the original. However he is currently offering only orange enameled caps. When I sent a question about black enameled caps he didn't say that he has black caps coming, just orange ones. Worth a try anyway.