Aircraft Pylon part ID ?

I have 2 of these items which I presume are some sort of aircraft wing pylon ?
The only markings I can find are shown in the pictures.
Each Pylon measures approximately 65 inches long by 9-12 inches wide.
At first I thought the green was moss or growth but its actually the colour they were painted
They must surely be modern by looking at what has been used in their construction i.e. rivets, cross head screws and staples
Any idea as to what they may have been used on.