Log on to GMail from a browser, click on the red word GMail and select Contacts. Are your contacts shown there? If so they've been synced at some point in the past. In this case they will restore as long as contact sync is on in your account settings. So if that is Google's default, then if you have data enabled when you do a factory data reset then it will start when you enter your Gmail account details after the reset. I'm talking gingerbread here, so apologies if options are different in ICS or JB.
If you want to be sure you just import stuff from your vcard file, make sure contact sync is off, clear data for Contacts Storage, then restore from your backup.