SMPFR

O.K., guys, here's a starting point.
From what I've gathered so far, it works something like this.

If your machine is "Before" July 9, 2001 (7/9/01) the VRM appears to be 34REP or 034REP

If your machine is "After" July 9, 2001 (7/9/01) the VRM appears to be 4F522

From my conversation this morning (really) with DELL tech support, there appear to be two VRMs currently, and they appear to be interchangeable.

The afore mentioned 4F522 which appears to be for the TUALATIN processor,
And the 4N594, which I'm "guessing" might have been for the COPPERMINE processor.

I did find one with the number C0140 which also has "Rev 01" on it, sounds old.

Now, all this information is NOT meant to completely answer your question.
Just to give you a starting point.
You have to determine which processor you have, then go from there.

Good Luck