Hard to say, but likely. "Reichsbürger" are the German monarchist an/or fascist version of the US Sovereign Citizens. Large parts of the far-right extremist scene are financed directly or indirectly by Russia, but a significant contribution comes as informant payments from the domestic intelligence services which have their own issues with far-right extremism. They did get some influx of new recruits during the Covid lockdowns, being mobilized again by (known) Russian financed right wing extremists.

The Russian wife of the third-rate minor noble they wanted to put in power tried to establish contacts with the Russian embassy, but at this point it is unclear if that went anywhere. Also these yahoos planned to get their coup recognized by the Russian government asap after pulling the trigger. So even if Russia didn't pull the strings, the people involved sure did think they would be doing Putin a favor.