Car 311 - Bayonet was manufactured through 2004 and then the screw latch was 2005 and on...both are Porsche OE. A hard top came with every 996 Cab unless you optioned your car with out a hard top.
Example: I bought my C4S which had an option Hardtop Delete. Thus Porsche did not put the hardtop receiving fixtures in my car so I must add/purchase them (see part # below). Here is the part number and links to instructions. Depending on the hardtop you buy (bayonet or screw fasteners) will depend on what parts you will buy to receive the hardtop. Photo below shows black Bayonet which is attached the hardtop and the silver pieces are what I must buy to receive the hardtop. The part numbers are below.
Hard Top:
Part#: 996-561-654-03 Electric (Driver’s)
Part#: 996-561-653-05 AS Fixture
Part#: 996-563-413-01 Hex Wrench
Install:
Hardtop Install on Cab - Rennlist Discussion Forums
How to retrofit a 996 hardtop to fit a 997 - Rennlist Discussion Forums
Wind Deflec
PM me if you would like clarification over the phone. BTW, eBay has many hardtops for sale.
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**Cheekybird**
1997 911 C2 - Arctic Silver
1977 911S Targa - Sienna Metallic
2004 911 Carrera 4S Cabriolet - Arctic Silver
1986 911 Carrera Targa - Guards Red (sold), 2000 911 Carrera Coupe - Ocean Blue (sold)