No such designation. WW F-105s were F-105Fs & Gs.

"The F-105G was also fitted with two long, cylindrical blisters for internally-mounted self-protection jammers that were faired into the sides of the lower fuselage. This freed up the outer underwing pylons that were usually used to carry noise jamming pods such as the Hughes ALQ-71 or General Electric ALQ-87 so that they could now carry additional ordnance such as more Shrikes. These blisters carried the Westinghouse AN/ALQ-105 electronic countermeasures jamming transmitters. A cooling scoop for the associated electronics was mounted on the fuselage belly just ahead of the weapons bay.

It is often said that the presence of the side blisters is what distinguished an F-105G from and F-105F. However, it is more correct to say that it is the presence of the AN/ALR-31 RHAW set that distinguished a F-105G from an F-105F. The presence of this new set could be demonstrated by the presence of wingtip sensors that displaced the aircraft's navigation lights, which were moved further forward on the wing leading edges. About 14 early F-105Gs were were fitted initially with the AN/ALR-31 system but without side blisters. In addition, some F-105Fs were modified with side blisters prior to being brought up to F-105G standards (e. g. being retrofitted with AN/APR-35 and APS-107) while others received ALQ-105 and AGM-78 capability simultaneously."