I know this much since ZS 3.2’s kernel has the vmxnet3 (10Gig) driver, and I’d assume ZS 3.2.1’s kernel would as well. The trick is VMware Tools isn’t integrated by default.
I built a OVA template of ZS 3.2 with VMware Tools pre-loaded, though it takes some post-boot scripting to actually run it. I don’t know if I have to repeat that build with the ZS 3.2.1 image; it might be enough to install the 3.21 update on a running 3.2 VM.
If you don’t need host-initiated shutdown, you can use the 3.2 and 3.2.1 images right away for 10Gig support and for emulated Intel E1000 NIC support. I never tried ZS on anything older than ESX 4.1, so your results may vary.