Thinkpad x220 - two different fan assembly modules?

I noticed in the x220 system service manual there are two FRU numbers for the fan assembly module: the first one being the SV/LV type with the FRU no 04W0435, and the other one being the ULV type with the FRU no 04W0436.

Now I'm one of the many individuals that has the high pitched fan noise issue on my x220. I've been researching on this issue and I noticed that many x220 owners actually reported they dont hear the high pitched noise from the fan. So is it possible that one of these fan assembly is the culprit? Theoretically speaking, if we know that which one produces the annoying pitch, we can just order the other fan assembly, replace it ourselves and solve the issue right there?

Lenovo Support - System service parts - ThinkPad X220, X220i

Also, for those that are late to the party and haven't heard about the high pitched fan noise issue yet, here's some info:

http://forum.notebookreview.com/lenovo-ibm/579172-high-pitch-x220-fan-should-i-send-back.html
http://forums.lenovo.com/t5/X-Serie...constantly-on-revving-up-and-down/td-p/425965

 

This was discussed a bit in this thread:


http://forum.notebookreview.com/len...x220-fans-not-high-pitched-2.html#post7539047


Seems as if the fans with the i7 system are the high pitched ones. I have the problem too.

 

As it's the same topic in both threads, I'm going to lock this one--please continue discussion in the other thread. Good detective work, guys