Looks pretty obvious to me the open end of the spring (small kink near end) goes against the floorplate and the closed end of the spring (with haprpin-like bend) goes under the follower. This orientation keeps the spring well away from the internal slide stop mechanism. You wouldn't want the spring peeking out from under the follower and getting tangled up with the slide stop.
My anyway.
Hey, you don't live in Indiana! How you doin' Atticaz?