Might I ask why you think they're both females? The other person used the lack of eggs as proof they were males, I believe. I'm sorry, but with completely opposite responses now, I would like to know your reasoning for saying they're females. Is it knob size or shape? Something else?
Can you post a few more pictures, showing body and legs also? I don't judge by knobs personally. Honestly, the neck length, body shape and size, and legs are good clues. Do either have a flap of skin (lobe) between the legs, or is the skin smooth? The one to the right has a very long neck, typical of ganders. The voices, is the tones low, (waa waa or hmmm hmm) or more shrill, (gee, gee?) goose are low toned, ganders are more shrill.