I don't think Gohan-Boo is "plee~~~~nty" enough to beat Gotenks-Boo, so a base Gokhan would be at least 1.5x stronger than the latter to me. With his boosts, he'd be stronger than Goku.
Base Goku handling Baby Gohan without a sweat is enough for me to take his side on this one. Given the time passed, training, stacked SSJ, Baby Boost, plus Goten's assist, Gohan shouldn't be worlds apart from a Gohan/Goku fusion. With effort, I see Base Goku pulling this out.