I agree it does not look like a Winegard product, Every ACTIVE Winegard product I have seen says, clearly, where you can see it when installed (on the front of the panel) WINEGARD.. This one does not, thus it is not.
Winegard is justly proud of their name and likes to print it on things.
Now if it is just a wall plate (Such as you find at the TV-2 or TV-3 posiition) it may or may not have a name on it..
But the plate shown is an active electronic device, if it was made by Winegard, it would clearly state a much on it's face.