You can edit / add/ delete Item Specifics before import in 'Edit' mode of extension (available in AliDropship Woo plugin and AliDropship plugin ver.1 (in Beta testing now). Find Item Specifics after Variations section of extension.
It's automatic. Click the extension icon on the top right of your Chrome browser and if it says "ver. 2.5.8.1" ... it's been updated.
... On a side note ... Chrome was updated today ... click the "3 dot" icon on the top right ... then click "Help / About Google Chrome" ... and it will update itself.