2nd gen tonneau on 4th gen?

[GoodmanS]

I have a fiberglass tonneau from my old truck that I was thinking of putting on my new one. I know, try it, but it is in storage right now. Both trucks are short boxes, and the color matches so it would be nice if I could use it. The specs show a 6'6" bed on the older truck vs 6'4" on the newer one. Is this an actual difference? I am looking at toppers so it's ok if its not 'perfect', but water tight would be nice. Any experience with this?

 

[EDankievitch]

Front bulkhead on the 12 has a concave bow to match the cab and the tail gate has that extended lip aft. If your tonneau rests up on top it will work if it slips over than will not... .