Helix has Gen1 and Gen 2 as well (G2N)
There are no G1 designated Humminbird Helix models. The first generation Helix models don't have G-anything. There was no G1 reference until there was the next generation Helix which are G2 or G2N.
When you see Helix models advertised and they don't have G2 or G2N in their model names, they are the discontinued first generation units.
Same as the Lowrance HDS units, no Gen1 designated models until there was a Gen2 model then the first generation are called Gen1. Lowrance has gone past Gen3 to the HDS Carbon models.