Having dealt with Glaser before I really doubt their fish, especially a rare one only recently collected, would end up mislabelled and mixed in with random shipments being distributed across the world. The fact that two shops on opposite sides of the world ended up with identical fish both mislabelled as "mango/magnum plec" suggests to me they have come from a large international wholesaler, probably based in asia somewhere.
Glaser said "They differ from all other members of the genus from there (L18, L47, L81, L85, L177) by the almost black ground colour of the body. Almost no spots are present." Both my fish and the OP's are quite spotty, neither of our pics were taken in ideal conditions with the fish not stressed. When coloured up and happy mine (and I'm guessing the OP's will too) looks very similar to this pic of L81 from PlanetCatfish; *Link*
Of L81 PC says "L081 is reported in DATZ to represent three very similar small spotted gold nugget plecos. Reportedly, the first is very hard to keep alive for any length of time; the others are considerably more hardy. While these fish may represent the range of population, it appears that the browner (as opposed to black) and finer the spots (amongst comparatively sized specimens) the more likely you are to have a hardy type. Little is know of what this fish looks like at adult size."
You're right the body shape looks tall, but I think it is exaggerated by the way the fish is holding itself on his hand. The Glaser fish looks far flatter than the OP's, so if shape is anything to go by I'd say that makes it even less likely that they are the same thing. Given variable nature of L81, the rarity of this new fish from Glaser, and the fact that this fine-spotted yellow-seamed Baryancistrus appeared in shops on different sides of the globe at a similar time, I still think my fish (and the OP's) are just variants of L81 and not some rare new wild caught import.
Glaser said "They differ from all other members of the genus from there (L18, L47, L81, L85, L177) by the almost black ground colour of the body. Almost no spots are present." Both my fish and the OP's are quite spotty, neither of our pics were taken in ideal conditions with the fish not stressed. When coloured up and happy mine (and I'm guessing the OP's will too) looks very similar to this pic of L81 from PlanetCatfish; *Link*
Of L81 PC says "L081 is reported in DATZ to represent three very similar small spotted gold nugget plecos. Reportedly, the first is very hard to keep alive for any length of time; the others are considerably more hardy. While these fish may represent the range of population, it appears that the browner (as opposed to black) and finer the spots (amongst comparatively sized specimens) the more likely you are to have a hardy type. Little is know of what this fish looks like at adult size."
You're right the body shape looks tall, but I think it is exaggerated by the way the fish is holding itself on his hand. The Glaser fish looks far flatter than the OP's, so if shape is anything to go by I'd say that makes it even less likely that they are the same thing. Given variable nature of L81, the rarity of this new fish from Glaser, and the fact that this fine-spotted yellow-seamed Baryancistrus appeared in shops on different sides of the globe at a similar time, I still think my fish (and the OP's) are just variants of L81 and not some rare new wild caught import.