Factory oil port plug info needed

Hi there, I'm hoping somebody can help me out.

I have a 96 Cobra which has an aftermarket oil pressure gauge installed. The gauge is giving me horribly inconsistent readings and I'm wanting to remove it. The only problem is that I no longer have the factory screw which plugged the port that I used for the gauge (next to the factory oil pressure switch). Does anybody know what type of "screw" I'm looking for, or where I could find one?

Thanks for your time and any insight.

Thanks for the reply. I don't have the factory one to compare length, but I can tell it looks like 1/4" NPT. I'm not able to find any that have an allen head like the original, which wouldn't be an issue if I get the right length.