Are these injectors original?

[chriskinzel]

Last fall my 91 would stumble when I got on it. The car has a very sorted past with no records at all. I figured that all I needed was to change injectors assuming that they where the originals. I pulled the plenum and checked the ohms only to find that everyone of them was 14.0 to 14.1. One set is orangey yellow and the other set is black. Are these original, and they have not shorted yet, or has a p.o. changed them. If they are ok why would it stumble? I have changed spark plugs.