I think I'd want sheetrock up first. *Reason is that it is somewhat of a fire barrier, and is probably required by code.

Found this in the Florida Building Code :

B3.3.2 Wood sheathing. Wood sheathing panels shall be
considered air infiltration barriers when applied to a frame
wall underneath an exterior finish and the following sealing
requirements are met:
1. Joints formed by the square edges of adjoining panels
shall be backed by a framing member. The joints
between panels shall be sealed, or both adjoining panels
sealed to the framing member using a mastic. For
joints formed by tongue and groove edges, the groove
of the panels shall be filled with mastic prior to mating
the panels.
2. The panels shall be sealed to the top plate using a mastic.
3. The panels shall be sealed to the bottom plate, floor
deck, or header and end joists using mastic.
4. The panels shall be sealed to the jambs or mounting
fins of doors and windows using a mastic.
Tapes of any type are not acceptable sealants for sealing
wood sheathing to wood members, mounting fins, or
masonry.

B3.3.3 Nonwood sheathing. Nonwood sheathing panels
including foam insulation boards, and foil or plastic faced
boards of other materials, shall be considered air infiltration
barriers when applied to a frame wall under- neath an exterior
finish and the following sealing requirements are met:
1. Joints between adjoining panels shall be sealed using
one of the methods given for wood sheathing boards
in Section B3.3.2, (1) above or, joints between adjoining
panels shall be sealed by pressure sensitive tape
with acrylic adhesive. Rubber-based adhesive tapes
shall not be used for this purpose.
2. The panels shall be sealed to the top plate using a mastic.
3. The panels shall be sealed to the bottom plate, foundation
wall, header and end joists, floor deck, or slab
using mastic.
4. The panels shall be sealed to the jams or mounting
fins of doors and windows using a mastic.
Acrylic-based tape may be used to seal metal and
plastic door and window mounting fins to the sheathing
panels.
Tapes of any type are not acceptable sealants for sealing
nonwood sheathing to wood or masonry building components

Looks like a wood barrier is acceptable as long as there is a barrier
sheet between it and the attic and mastic is used in the groves before
assembly. Sound right?