If you want to identify whether its the injector or metering head, swap the fuel connections over on the metering head (will be tricky though as u will have to sort of force the pipes over to different connections), if when swapped number 2 still over fuels, it would be the injector, and if the fuelling problem swaps to another cylinder it will be the metering head.

As for the injector seating its almost impossible to seat them wrong, that said i doubt u have even removed them anyway?

Do urself a favour and go EFI, KE Jetronic is PANTS.