A/c o-rings 1kz-te engine

[Kingo125]

Hey guys need some help with my A/c on 2003 hilux 1kz-te engine. I got a new hose from the wreckers and it had a black o ring inside the fitting threaded end. However the pipe on vehicle had a groove with a green o ring already on it. The green one makes sense as it slides into the new hose fitting and would seal that way. But i cant work out the black one. The hose fitting in question has a taper inside it and the pipe a sharp edge.. looks like the oring wont seal properly anyway. Just chasing some help before i attempt to fill with gas. Cheers 

[trentmeyer23]

Some are green and some are black.

You will typically find black in R-12 systems.

https://www.google.com.au/url?sa=t&source=web&rct=j&url=http://www.compressorworks.com/Upload/Four%20Seasons/documents/Tech%20Tips/English/4S%20376%20O-RING%20COLOR%20CHANGES.PDF&ved=0ahUKEwjn2cPf7tjXAhVRQLwKHeC1BW0QFggfMAE&usg=AOvVaw1Ypm3_Eo0OOnC584rm80kH

[Kingo125]

Yeah ok thanks but my issue is the black one looks out of place regardless of colour. Maybe the wreckers just put it in there. I should of got some pics

[Kingo125]

The fitting is like this with a green o ring on it. Which slides into the hose fitting. The black o ring was inside the hose fitting on a taper. Just doesn't look right