Inspired by this answer to A good example of a Finnic or Finno-Ugric language that can be confused with Finnish? I want to know more about the Tamga signs. Did they constitute a writing system? Is their derivation known?
The answer depends mainly on what to be considered as a writing systen. If we regard a picrtogram writing system (e.g. similar to Daba script) to be a writing system as well, then the answer to your question is positive.
A travelog by Ahmad ibn Fadlan mentions two kinds of writing system used by who later were identified as Komi ancestors called Wisu (which sounds similar to Balto-Fennic Veps and Russian 'Vesj'). The facts are, however, mentioned not in an academic publication but in a local newspaper (in Russian).
Later, a local amateur researcher (and a gymnasium teacher) mentioned in 1850 that the system of 'pases' was used for writing down daily costs, obligations, loans, etc., including dates, types of articles and names of persons.
The other system of writing, that of 'shipases', was supposedly an adoptation of some North-Iranian alphabet, also used in Bulgarian Khaganate at its pre-Islamic days as stated by another local researcher in the 19th century (source in Komi and Russian).
The systematic nature is confirmed by the fact that the symbols were used as ornamental details and/or inscriptions by representatives of clans other than those owning the Tamgas.
The pictographic nature of the system is confirmed by the fact that the symbols had various meanings and interpretations. E.g. the sign X could mean a facet, or crossing beams, or a new ornament (vyl ser), or fire, or sun, or a cross as a symbol opposite for Christianity (the source in Russian) plus a clan could use any sign in some private and particular sense.