Here's an interesting variation of the 1675. Known as the "mini-dial" or Radial dial, This dial was used on some GMTs during the mid-70s. Dating is always chancy at best with Rolex variations, but some feel this dial was used circa 1975 or so till about 1978-79 on some pieces.
Note the smaller indices along with the slightly larger markers at 6 and 9. The variation also used a bit longer coronet.
Photo from a vintage web site--credit Bob Maron,
