If you are trying to price everything that would put your to-be-purchased-from-GP-HMMWV in the configuration or condition you want it, you can probably figure on $5500-6500 for a complete manual turret set up with Grade 8 hardware (minus the actual M23, Mk64, Mk93 Weapons Mount). I couldn't sell one of my complete turrets for much less than that, and I'd never be able to replace it for what I have into it.
Turret Weapons Support Ring $3500
Turret Weapons Station Tray/Pan $800-1000
Bearing $400-1000
Hatch Assy $250-450
Lock Ring Assy $300
Turret Bearing Retainers (6pcs) $300-400
Weapons Mount/Chicken Foot $300-350
Weapons Mount K-Bar (underside support for the Weapons Mount) $200-300
Back Pads (2pcs) $100
Pintle for Weapons Mount $60-100
Traverse Lock Assy $40
C Pillar Crossbar $500-600
Windshield Frame Brackets for Weapons Support (2pcs) $80-100pr
4x Resilient Mounts for the Frame Brackets to Weapons Support Legs $40-50
Windshield Mount Shim Plates (2-4) $10each
Inside Windshield Frame Nut Plate for Frame Brackets $30-40 each
Turret Hatch Latches (2pcs) $20-45pr
TOW Base Hatch Cover $25-40 or
TOW Mounting Bracket $50-100
Gunner Seat Mount Brackets $30
Gunner Seat/Sling/Swing Seat $30-100 depending on type
Rubber Bushings for Weapons Support to C Pillar Crossbar $20-30/pr
Snubber Plates for Above Rubber Bushings $10/pr
Tubular Sleeve for the Weapons Support to C Pillar Crossbar Bolt $10
Threaded Rod for Weapons Support to C Pillar Crossbar $5-10
Assorted Grade 8 Hardware, mostly 3/8-16 bolts, Nylok nuts, washers, minimum $100, probably closer to $125 or more
So whatever the above adds up to, along with whatever small parts I missed. You may be able to scrounge here and there get it a few hundred cheaper but competition is fierce for turret parts.
Get your truck, leave the roof plug GP put there in place until you scrounge the necessary turret parts over time, a $300 piece of Sheetmetal, vs paying $1500-2000 for used 4 man rag top and doors, that you could apply to your turret kit.