Yeah, you can try that since GF will see it as a seperate person even though it's the same address.
If you sign up and you see the your next billing date is just a month away from your sign up date(instaed of being two months away), then that means they didn't give the free month, so you can just cancel within 48 hours and they'll give you a full refund if you wanted to do that.
Also thanks alot man and check your inbox.