10316 is the Ford "basic" part number, all alternator regulators are 10316, the prefix and suffix indicate the application.
The C5AF you reference will work fine as likely your Cobra doesn't have AC, a power top, etc. Most any aftermarket regulator will do the job unless you are looking for a reproduction unit to replicate the units used in 60's Cobras. All of the current aftermarket units have "low" covers and are electronic, the O.E. units have "tall" covers and are electro-mechanical type.
Here is new:
https://www.summitracing.com/parts/s...caAk9IEALw_wcB
And here is original type:
https://www.google.com/imgres?imgurl...act=mrc&uact=8