What injector is this?

So while my engine is out of the car im refurbing all the parts i can.

Decided to refurbish my inlet manifold. Took the injectors all out as im going to get them all flow tested, however one looks different to the others. Can anyone explain why this one is different....


Look at the tips, one is black...its not dirt or oil it is actaully a different colour




Also the top feed part is differnt this is what the stock ones should loook like



this is what the odd one looks like, you can see it has three prongs

Does the odd injector have a number or anything stamped on it?

Each injector has a number stamped around the top. three Match but odd one has a different number.

All look standard to me 440
Or 444
Just the mesh missing ?

What's number then mate? I can't quite see the whole number in the photo.

the numbers on three of them are

0A500Y21D

the odd one is

0A502X20D