Number of platters used in WD1003FZEX and WD5003AZEX

At Micro Center I performed an entirely un-scientific test and weighed WD1003FZEX and WD5003AZEX bulk-packed drives in my hands and they appeared to be the same weight. I wonder if they use the same number of platters, with the WD5003AZEX either having one less head assembly or being short-stroked (if that’s the correct term for a drive which only uses part of a platter). I’m sure someone at WDC knows, but does anyone here know how many platters are in both drives?

UPDATE: I think I answered my own question. By surfing around, I found that they both use a 1TB platter, so the 500GB version would only have heads on one side, which would explain why they weigh close to the same.

You can determine the actual number of heads by dumping the drive’s firmware with a tool such as SeDiv.

SeDiv WD Read ROM & Modules:

There is a “head map” in ROM module 0A.

Another way is to use HD Tune:

How to determine number of heads using HD Tune: