These do look like G models to me. Some history.
G1, long range fighter bomber based on the A4 airframe. Build by Arado and Fiesler. The G1 had provisions for a centerling and wing fuel tanks (wing tanks adapted from ju-87 tanks). Only 49 were built.
G2, identica to the G1 except it was based on the longer A5 airframe (extended engine root area).
G3, went into production in 43. Standard equipment included a PKS 11 directional control system (navigation). Focke Wulf designed bomb racks and external fuel tanks and provision for robot camera.
G4, G5, G6, G7 were projects only.
G8 was based on the A8 and had most of the modifications found on the G3. Additionall differences were that it had MW50 (on A8) replaced with a 25 gallon fuel tank as standard. Relocation of the ETC 501 racks forward. Production stoped in 44 and further G8s were produced in the field by modification of F8 models.
There were probably some incomplete G conversions of the F8 in the field.