Does Rally the Troops buff Recruit units?

Yes, Rally the Troops does buff Recruit units.

According to RiftJudge FAQ #418, Rally the Troops applies to all friendly units played or created, including tokens, unless the card text specifically excludes them. Recruit tokens (which are defined as 1 [M] Recruit units in Rule 184.1) do not have any exclusion text that would prevent this.

As outlined in the Rally the Troops mechanics (see the <direct_match> entry in the retrieved context):

• Rally the Troops creates a global, turn-long condition.
• Each time you play or create a unit, a delayed trigger is placed on the chain to apply a Buff counter to that unit.
• Per Rule 702.3, a unit can only have one buff at a time. If the Recruit unit already has a buff counter, it will not receive another one (Rule 426.1.b.1).