The Black 1210 is sold thru online, musician, DJ outlets. The silver 1200GR is sold thru audiophile or Technics home audio dealers. You can get get discounts on the Black 1210 thru places like Guitar center, etc. Audio dealers CAN get the black 1210GR however, the music, DJ dealers CANNOT get the silver 1200GR's (although I'm sure someone knows of an exception or two). There are much fewer silver 1200Gr's and most audio dealers have low or no stock. There are a couple places like Value Electronics and USA Tube Audio that seems to buy at larger volumes.
Where did you get that information from?
The DJ model is mk7, not the GR (no matter what color).
The SL1210 mk7 and SL1200GR are different turntables.
The GR available in two colors S (silver) and B (black).
The mk7 also available in two colors 1200 mk7 is silver and 1210 mk7 is black. The stock availability always change, no matter what model.
Like it was ages ago Technics supply those turntasbles in two colors, it was always like that with 1210 mk2 and 1200 mk2