Not confirmed yet, but latest info seems to indicate that the GL59 and GL60 were Goldring's first heavy platter offerings.  There are no Lenco versions of the 59 and 60.  The GL59 was first sold without arm, then when Lenco released the L70 with arm, Goldring supplied the GL59 with the same Lenco arm.

The first heavy platter from Lenco was the L70, all 3 decks were available during the first years of the 1960s.  About 1962/3 the 59 and 60 were discontinued by Goldring, and they rebadged L70s as GL70s.