As said Barone necks are for Selmer clones they are not only missing the octave key but they are much shorter and of a completely different design.
In the aftermarket neck market there are definitely two different strains , one is made up by the makers or resellers of necks which are targeted at the " standard" horns on the market: Selmer, Yamaha, Keilwerth......... some others make neck that are close copies of the original and that are actually able to modify their design to specs.
These makers are the only ones who can actually REPRODUCE a neck as it was on a vintage horn!
Gloger belongs tho this second type of makers. Another place , also in Holland, which somehow specialises in Martin necks is the Blazersatelier in Tilburg
http://www.blazersatelier.nl/reparatie-restauratie/
here they show in particular a Martin Bariton neck sold for 335€ (and since that is VAT included for sales outside the EU they should sell without 19% VAT)
http://www.blazersatelier.nl/nekken/
Thanks Milano, an interesting link - and their prices for the horns are very reasonable!