No, sorry. The four pedal jacks are identical to the Motif-series with one difference:
_ A dedicated Sustain pedal jack that can be set to do Half-Dampering when set for and an FC3 pedal is inserted or can work as a simply ON/OFF sustain pedal with a standard momentary.
_ An assignable Foot Switch which can globally be assigned to any number of functions. It too is a momentary function (On when engaged, Off when released). This can be set to send cc067 Soft (I've not seen a Data List for Montage to determine if it responds to this message). btw - a dedicated electronic piano is more likely to have a three pedal option, as Sostenuto, and Soft (una corda) are functions principally found on only one instrument the piano. The assignable FS can certainly be set to do Sostenuto (cc066) and the Montage will respond to this message.
_ Assignable Foot Controller 1 takes a Yamaha FC7 sweep pedal and is assignable per Performance to control whatever you'd like. The default, like on the Motif-series is cc011 Expression.
_ Assignable Foot Controller 2 takes a Yamaha FC7 sweep pedal and is assignable per Performance to control whatever you'd like. The default is to act as the SUPER KNOB, which allows you to control different aspects of each of the possible 8 PARTs under Keyboard Control in the current Performance. Each Performance is 16 Parts, eight of which can be set to "Keyboard Control". So all movements of the SUPER KNOB function can easily be done while both hands are on the keyboard.

Does an FC3 pedal work any differently than an FC3A? I noticed that Yamaha is giving away FC3A's as part of a promotion. Would there be any advantage to replacing my FC3 with one of these?

They are functionally the same. The FC3A has the model name, Yamaha logo and is the new version.