As you ask: Every prewar Mannlicher – Schoenauer sporting rifle or Stutzen has such a barrel band with sort of a sling swivel base, see the catalog pics above. The screw of the stirrup swivel fastens the thin, hollowed out and fragile foreend to the barrel. If the foreend was not fastened to the barrel this way, a forced pull at the sling would break the wood. Most often these barrel bands are not fastened to allow for lengthwise expansion of barrel or wood. But it is easy to fasten it by a bit of soft solder or even epoxy and mount it with a conventional swivel.
Imho on this M1925 rifle the factory stock had the foreend shortened and fitted with a horn or ivory tip to alter it to British and American tastes. The now short stock necessitated mounting a sling swivel on the barrel. I have once seen an opposite modification in an Austrian gunshop: Here a Mauser Magnum actioned .350 Rigby rifle had it’s iconic short Rigby foreend lengthened to M-S rifle shape by installing a very long contrasting foreend tip