Yeah, when you buy 1 gift during happy hour it will multiply it automatically at the end, you don't do anything. You'll just go to your page and it'll show between 2 and 4 gifts(assuming happy hour) with their own links.
Looks like this deal is dead, just saw this posted on the Origin.ea facebook page from 5 hours ago:
Effective immediately, the Mass Effect 3 promotion on Origin that included a bonus copy of Battlefield 3 is ending. All customers who pre-ordered Mass Effect 3 during the promotion until now will...
Thanks, I missed out on the last time they did this by about a minute. I added them to my cart but the sale ended before I decided how much I wanted to get, glad to get in on this finally.
I just tried, the initial sale page shows the discount price, but the checkout and individual item pages don't show the discount any longer, dead I guess?