And Randy, the numbers you just listed are the Ford part numbers. Not the O2 sensor manufacturer part numbers. 9F472 and 9G444 look exactly like most other Ford numbers. As Orange Peel pointed out the Bosche number is actually different. I'll bet Ford uses Bosche sensors. I dont know if the OEM parts will have the Bosche number on them, but maybe. See if you have that stamp on them.
Also... one more time.... When we we're developing the MIL Eliminators I looked at the front and rear O2's on an NGS. Without cats the signal looked the exact same on the fronts and rears. Which means they were toggling around the same point, the stoichiometric point of 14.7:1 A/F ratio which corresponds to a Lambda of 1.0. If indeed the sensors had different Lambdas, then the rears would have had a different duty cycle on their waveform. They didnt, they looked exactly like the front. Therefore they are the same sensor...
Plus as Orange Peel stated having the same sensor in the front and rear works just fine... And other people have observed this also.
 I went to Bosch's web site and poked around. Here's what I found...
- Gasoline engines (Lambda =1)
- Fast light-off (<10s)>
- Wide operating-temperaturerange
- Stable control characteristic
- Improved exhaust gas values
- Low power consumption (7 watt)
- Isolated ground
- Small size
- Service life > 160000km
- Super fast light-off available
This is the ONLY sensor they list for engines like ours and it is LAMBDA=1.0 They list another type for gasoline direct injection engines and has a different monitoring scheme, but this is the ONLY narrow band sensor they show for engines like ours... heres the link...
NOW I'm done with this...