they are definitely different species.
the Ancistrus (bristlenose) do require wood in their diet and they are mainly vegetarian. they feed primarily on algae and have the distinctive log gut of typical of vegetarian species,,,while they can eat many fish foods their diet should consist primarily of veggies.. wood is thought to be a good addition to the tank as the BN like to hide in the wood and may benefit with rasping on the wood.
Rubbernosed do not have the same requirement in food and at least for now are , omnivores they benefit from a varied diet. they will eat algae as well as other foods