The original, since 2003.
I can't remember if anyone tested this previously or not, but I did this as part of an All Characters Ending run (Which somehow managed to break itself, no surprise there).
I wanted to test whether or not the Mantra skip had an effect on unlocking Hell Temple for 100% Inventory/ All Characters. As it turns out, you can perform the Mantra Skip in those categories too. You do not need to seal Palenque's Mantra (Or any of the others for that fact) in order to take the lava warp and unlock Hell Temple.
Obviously in a speedrun you might as well finish the Mantras off anyways, because you can't fight THE BOSS unless you do.
I wanted to test whether or not the Mantra skip had an effect on unlocking Hell Temple for 100% Inventory/ All Characters. As it turns out, you can perform the Mantra Skip in those categories too. You do not need to seal Palenque's Mantra (Or any of the others for that fact) in order to take the lava warp and unlock Hell Temple.
Obviously in a speedrun you might as well finish the Mantras off anyways, because you can't fight THE BOSS unless you do.