Yes that is right. It last 2 - 3 months and the payment will be release after a month or two. So basically, it will took 5 months or more before you get your reward. Sometimes if you are very unlucky, then you'll get none after your hardworks.
Or more than that. It depends on bounty campaign sometimes there's bounty campaign does last for 5 to 6 months and the distribution 1 to 2 months. Base on my experience i still remain in signature campaign 5 to 7 months and I wait for my reward in 1 to 2 months. But if you want a smart strategy, you should join in the middle of the campaign or 3 weeks before the end.