I have a 19 with the multi-pro tailgate. Currently I have a BAK F1 on it and the fit is fairly terrible.
The front seal was far too thick, so I had to leave it off, yet the rubber trim on the cover does not sit down flush. The rep states the gasket should squish down, but the bolts for installing it are not long enough to allow for that to happen. If customer service cannot resolve, I may have to install my own, thinner seal. While I might be able to get it together with the thick seal once, it would not support frequent removal and re-installation.
The drain tubes are the same size as the drain holes in the upper corner of the bed, so right now they're just stuck in there. As with the seal, I may put on my own, slightly smaller tubes, should customer service not be helpful and I decide to keep it.
Lastly and the most important, the multi-pro tailgate is not flat. The center section has a slight bow and as a result, when the mounting rails are flush with the bed rails, the cover will not close. To resolve, I lifted the mounting rails to allow the cover to close once the gate is closed, but it will not work in reverse because the gate hits the cover (which was the main feature that caused me to upgrade to the F1). Beyond that, the rear corners have massive gaps, thus are not sealed nor secure.
If you have a multi-pro gate, do be careful with the truckhero (Extang, BAK, Undercover, Gator, etc.) covers. Hopefully the customer service rep I'm working with gets back to me soon, otherwise I will be asking for a refund and looking for another manufacturer.