O2 sensor question

[Turbotungsten]

I disconnected my o2 sensors when I pulled my engine and it has been so long that I need help with reconnecting them. The green wired ones are the front and the white are rear, correct? Now as for the front ones, how do I know what wire goes to what sensor (I know green to green and white to white, but how do I distinguish between sides. Also, are o2 sensors changing A/F in a cold start up, or do they only function at normal operating temps? Thanks

 

[lostsoul]

the green one is in the back... both are the same except for the size of cable.. one is 10" and the other 15" I believe