No, 4.6.0 is a “stop release”: IIRC you can upgrade from any version of a “stop release” to the next release (at least this is how it was in the past), though @jovirkku explicitly stated otherwise for 4.6.0→5.0.0 using the GUI updater.
Technically there is no reason why one should first install the last version of a “stop release” before upgrading to the next release; but do not omit installing any version of each “stop release” in an upgrade path, or your SailfishOS installation will be harmed (i.e. needs to be reflashed).