Catalytic Converter, O2 Sensor & EGR Questions

[Von]

first find out if the car is CALIF or Federal  car,  hood sticker missing?, makes that hard
the old 02, has plug,  
fed is 3 wires and one blank pin of a 4 pin connector
Calif is 4 wires and 4 populated pins.   with white connector and flat pins
the fed 3 wire connector is black an was round pins.
hope you have the old sensor intact,  with connector still.  

the bosch universal hand wire sensors are good too.
15726-3F  (for sure most common sold car 48 states.) but only looking first counts.
15730-4C

last  2 digits  above  are mine 3 mean 3 wire,  F means federal  sold as low as $20 a real money saver.  sans connector stock with adapter,

The old had white connector and flat pins. It also had 4 wires. The new one was a universal that required me to splice Into the old wire with the connector side. The new had a blue (signal) white (ground) 2x black (both heater.) The old wire with the connector had the same color wires (blue, white, 2x black) the only ones that could be swapped are the black wires but have been told it doesn’t matter for those. Is there any diagram that shows on the connector end what the 4 wire are called or are for so I can confirm the proper wires were spliced to the right spots. Also I was told that the 2 black wires did not matter which one went to which. Does that matter or could they be swapped.