The difference between the Lodestar 3 and 3D is the frequency coverage. For purposes of clarity, the variant designators of Roman numeral III is used interchangeably with Arabic number 3.
Technology: Solid state.
Variants: Lodestar, Lodestar II,  Lodestar IID, Lodestar III. and Lodestar IIID.
Frequency ranges:

Lodestar 3 - 250 to 550 KHz and 1600 to 2800 KHz, Included are spot frequencies for 500 and 2182 KHz, Bandspread range is 285 to 315 KHz.
Lodestar 3D covers 250 to 550 KHz and a small band of frequencies of  plus 18 KHz and minus 17 KHz centered on 2182 KHz. A spot frequency for 500 KHz is also provided.
Modes: for both variants: A1, A2, A3 and A3H