Part number or screw size for fuel cap chain

I got a 2005 Rinker 262 Captiva Cuddy and the screw for the fuel cap chain is missing. Since I live in europe i tried M3 and M4. M3 is too small and M4 is not gripping the threads. Anyone has a clue which thread and length it should be on that small screw?
The research I've done says it should use a 6-32 x 3/8” UNC Pan Head. Is this correct?
The research I've done says it should use a 6-32 x 3/8” UNC Pan Head. Is this correct?
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