The part number is 570862. The eBay listing references that part number. Their picture shows nibs on the rotor. The rotor they sent me has no nibs.
Ask for a refund. "Item received does not match picture / description" is likely going to be sufficient grounds to get you a refund, without even shipping the rotor back.
If the parts physically fit, I might be interested in giving those unwanted parts a new home. I'd like to accumulate all the parts I'd need to kick my Euro 3 C5's ECU to the curb, just for fun.
It is concerning that you are measuring less than 5 volts across pairs of yellow alternator phase wires. When I ran this test on my 1999, single phase Bullet alternator, seems like I was getting voltages in the high 30s VAC range, tested open circuit and revved up a bit. You tested with the rect/reg connected, or open circuit?