The pictured grips would be for a Detective Special or Cobra.
The Diamondback 2 1/2" model came with square butt "Service" type grips, the 4" and 6" came with Target type grips.
The target type came in an early version with the checkering border in a half circle under the medallions, the later version with the checkering border in a slanted straight line under the medallions.
Early version had silver medallions, later had gold.
Diamondback 2 1/2" Service grips:
Early Diamondback Target, curved border checkering. Silver or gold medallions:
Diamondback later grips, straight line checkering:
Fakes are usually made of either garish foreign hard wood, or extremely plain wood. These almost always have medallions that look like Colt until you look close and see there not, and they almost always have brass grip screws and bras screw bushings on both sides. Colt were blued or nickel steel and with one bushing on the right side grip ONLY.
Current Asian fake Note the brass screw and bushings and the plain wood. Colt grips were American black walnut: