Found some more info. The 191r was made in Nuevo Leon, Mexico by singer mexico. The one on youtube.com (in Spanish) sounds like a thrashing machine. It came in white and tan, also. There are some for sale in border cities (El Paso, etc)on letgo.com.
The 191 appears to have been made in Europe as well. The 191J (in German, I think) on Youtube.com sounds nice and smooth like the other old singers.
It appears to be close in design to the 185K.
bkay