ntropy

Hi,
I am helping a friend find a 2005 G55k steering (gear) box and I've become confused in my search due to the change in part numbers.

This is what I have found...

First, I found that it was part # 4634600401 - it then stated that it was discontinued and changed to part # 4634600001-88.

It once again stated that part # 4634600001-88 was discontinued and changed to part # 4634600401-88

Are these parts the same (other than the part #) and are they interchangeable?

Thank you in advance for your time and help.