That's not an actual build-up, though.
With Sanji and Queen, we got the "judge's son" lingering plotline since Chapter 995.
20 chapters later, in 1015, Oda finally continues it.
We don't have anything like that for Zoro and King.
This is why if Zoro and King do end up fighting, it won't be the main event for Zoro, the way fighting Queen would be the main event for Sanji.