Well, I've turned 180 degrees. I got bored, or whatever and put the GOOD seat skin on the other side. I need the CORRECT seat skin ordered. Turns out the difference is that someone just kept going with the sewing machine, sewing a "stitch" into non-joining fabric.
Chris, here's the magic secret to putting the skins on...
First, get the seat out. When you're taking the old skin off, notice which parts of foam are stapled to the board. This tells you that the foam was in place when the internal anchor pieces were stapled down. On my backs, there's a small square section in the bottom middle, an upside-down U that goes over and around it, and a top "mostly" long rectangular shaped piece. The two lower pieces were stapled to the surrounding piece of fabric.
Use your old staple holes as a good reference point. Place the bottom square piece where it goes (lined up with the bottom). I actually left the piece out, and stapled as close to the edge of the fabric as I could and followed the original staple line (removed all staples of course). I then squeezed the foam into place. Next, I put the upside-down U into place, and did the same thing (it needs to be in place or else you'll never get it in afterwards). Then put the top piece in, smushed it as much as I could, worked the back over the back of the seat frame, and got the new fabric TIGHT as close as I could to the original staples (if you don't get it far enough down, you'll see the staples and board from the back deck). Then tacked in the sides and bottom and voila!
One thing, you'll find the foam wrapped (or partially wrapped in cellophane). I left that in place if it was in decent shape, but some had to be removed. Then cover it with Saran Wrap or other plastic wrap. DO NOT GO SPARINGLY on it. This is what keeps you from having mold/mildew in the foam from a good rain. Of course, the top part is the most important.
They get easier as you do more of them... I think the last one took maybe an hour.
Understand though that you're replacing with the same materials you originally had and the life expectancy should be similar. If I weren't this far into it, I'd have had a professional do it and use TOP GRADE stuff. However, my boat is 4 years old now and a lot of the problems are sun damage and stepping on the seats. DO NOT STEP ON THE SEATS!
To be most honest on this, if I had to do it again, I'd probably see about putting boat cover material as seat covers.. not sure if it's a good idea or a lousy one.