Pianotech

Today I serviced a battered Baldwin studio console with a limed oak finish in the orchestra room of a local high school (#259073).  Out of curiosity I looked up the serial number (in my trusty Pierce Piano Atlas) and found that it only dated to about 1984.

I was surprised that limed oak pianos were still being sold as late as the 1980s; I always though that this was a 1950s phenominon.

To make this matter more confusing, today I coincidentally tuned another Baldwin studio console.  This one (SN 231393) was supposedly from 1966, but my research showed it to be 1979 (which agrees with the gloss walnut finish and condition).  Why are Baldwin SNs so confusing?