I THINK that "HS" stands for Hy-Score, one of the importers of the Rohm Gesellschaft (RG) revolvers before the Gun Conrol Act of 1968 restricted imports of small guns.
Those guns were often sold by mail-order and were very cheap, often as little as $9.95. They gave rise to the term "Saturday Night Special." While they had all passed German proof, they were not noted for durability and most have broken or been discarded long ago.
If the gun still works, it might have some value as a shooter and plinker; there is no collector value. I strongly recommend using only standard velocity ammo, not high speed any of the "hot" .22 ammo.
Jim