possible to trade B grade weapons?

Is it true the only B grade weapons that can be exchanged are Top B one-handed for 2 handed dual fists?

example: exchanging an AOBA for a Bellion Cestus

Yes and only that way too, can't make fists into a AOBA, for example.

all top b weapons
but only to fists cant trade for anything else

all top b weapons
but only to fists cant trade for anything else

Which seems very dumb, as only one class in the game has masteries for Fists. They should either make it available for all weapons or none at all for b-grade.

Rumour has it that it was done to encourage the playing of Tyrants in Korea as no-one played them.

thx for the info everyone. I thought thats what I read but wanted to make sure.