Those actually look like the Standard line from around 1981-82. They had the classic lugs but those straight spurs like that. They came in four colors: black, white, red, and blue.
Ludwig went to the 6 ply shell in 76, so that 3 ply granitone shell you are referring to went out of production. I've heard (though you can't always believe everything you hear) that some mixed shell (3 and 6 ply shell) kits were sent out during the transition period. Since it cost less to make the 6 ply shell vs the 3 ply shell ...... and the Standard was a budget kit ..... I suspect the Standard line (with 3 ply granitone shell and standard hardware) ended in 76. Very little info. appears online. As far as the S/L line ..... seems only the 82 catalog scan is easily found. But that line might have been birth in 76/77.I thought all of the Standards had that granitone interiors, and most of the Standards I've see have been 3 ply.
Go back to the scan from the '82 flyer. It says right there - 6 ply bass, 4 ply snare and toms. Sometimes we don't see all the plies when we're scrutinizing the edges.I thought all of the Standards had that granitone interiors, and most of the Standards I've see have been 3 ply.
In any case, this would be a solid kit IMO. The traditional depths are a definite bonus.