Latitude 7214 Rugged Extreme Dock Compatibility

Hi. 

I been trying to find out the part number of the dock that is supposed to be used with the Latitude 12 7214 Rugged Extreme. but i'm a bit disappointed there is no part list anywhere on the support website. because i have seen several docks online and seems that the pogo pin alignment checks out but it would be a gamble to buy one of these without confirming it by the compatible part number. 

Also by looking at pictures on Yahoo Auctions on japan i know theres a keyboard model on Japanese language for the rugged line but again i have no part number list (the Japanese keyboard is mentioned on the manuals, and by the photos i know it exists)

Thanks.