This fascinating 1952 card is perhaps illustrative of an initial series of GE electronic tube ads which may have been the precursor to those found on the surcharged cards.
Note that the comic theme is consistent with later known ads, but the orange/blue color scheme is reflective of those used by GE appliance advertising from the 40's period. It is interesting to note also that ETR-555 lacks any "-2". I would conjecture that this portion of the code in the 1000- ad series represents the second group of ads.
Place mouse on image to see the reverse side of the card.