Is there a script to get Serial number of a Dockingstation via IP address of the laptop ?

If the vendor exposes it via WMI on any level it's possible using Powershell or vbScript by leveraging WMI.

GET-WMIOBJECT win32_bios -computername 10.0.0.10

in Powershell will pull up BIOS details on the laptop in Powershell for a remote workstation of IP address 10.0.0.10

It would depend on your vendor (IE: Dell) where in WMI the Docking station might make the change.  I would hazard it as "probably not" though.

Sean