For those not in the know... RCA TK-760s are a 'studio' version of a TK-76. Still a 76 in the middle but with a 'build up kit' added. They could be purchased either as a 760 ex RCA or one could buy the kit and retrofit it to one's 76.
As all the 76's I've come across were RCA blue, I suspect the cream 760s are ex factory.
And continuing on the trivia theme... the "76" comes from their year of [intended] release
However very few made it into the market place before 1977.