No I am the GM
A player was explaining this to me, but I was merely confirming.
I was just confirming that my assumptions were right, in that it didn't fit the very strict requirements to be a black blade.
the Estoc does seem kind of overpowered.
it can benefit from being used as a two handed weapon, and can gain weapon finesse but only when wielded as a one hander.
hmm or maybe that's just versatility...
its damage and crit averages will also be higher/ better.
It's a bastard sword rapier. It can be used with weapon finesse only if you have the exotic weapon proficiency feat, but once you have that you can use weapon finesse with it in one or two hands. You may have missed that part.
As far as Bladebound goes, no, he can't. But the fact that the Blade Adept arcanist ignores that is dumb, and it's not a bad houserule to allow Bladebound magi to take any one-handed piercing or slashing weapon within reason as their black blade.