City plans for use by civil government in the USSR, with ‘Local Coordinate Systems’ were produced by GUGK (Central Administration for Geodesy and Cartography of the USSR Council of Ministers - Главное Управление Геодезии и Картографии при Совете Министров СССР).
These are to the same specification, coloring and symbology as the military city plans, but omit geographic coordinates, the street index, ‘spravka’ and ‘important objects’.
Local coordinates were established separately (and secretly) for each map, but the projection is the same as SK-42 projection, with identifying values omitted and a local grid applied.
GUGK plans of the Latvian cities of Riga and Valmeira can found here