I'm fairly certain they're the EMGO tank, especially given the source of their new alternator rotors.
The price is also consistent.
I'm intrigued to see what they're doing to the filler neck - I just checked an EMGO tank against an original Roadster tank from my '73, and they're identical apart from the EMGO aperture being slightly larger (non-issue).
Both tanks are in bare metal, and with an OEM (Ceandess) cap fitted, if the cap is opened beyond the vertical it will touch the tank behind the recess -
this is the same for both tanks.
With a layer of paint on the hinge part of the tank this provides the necessary 'padding' - The original tank was on my bike until recently, and had no issues with the cap fouling when open - it wouldn't go beyond vertical.
If the painter elects to leave the whole filler neck unpainted then I'd anticipate problems - and some rust also :roll:
To answer the question, they're the best available, and I don't see them being bettered anytime soon; almost on a par with the original.
It should be self-evident which is the new tank in the following comparison photos :wink: