Arizona Swinger

looking good, I have a question regarding your Headrests using the picture below did yours look like the one on the Left or Right ? I just got a 1970 Dart with a recovered bench seat and came with new headrests in sealed plastic (left) and when I removed the old ones (Right), noticed an obvious difference in the post lenght and notch location and the new ones won't lock in. I see that they make ones for bucket seat and bench seats and hopefully someone just ordered the wrong ones, Thanks for any help you can offer