Yeah sorry there's usually no way to tell unless you see it grow before you smoke it. But, sometimes you have a chance. Indicas are usually a denser bud, and not quite as light, airy, and fluffy as sativas. Indicas tend to have a darker color than sativas do. Sorry but there's just really no straight forward rule until you've smoked it. Your best bet would be to find a connection that knows what its selling.