I paid $500 for that DX metal pump topper 10 years ago...I know..I know,but it's the only one I've ever seen,it's near mint condition,and it was during the pre recession "we all have disposable income" times and I just had to have it,as I collect both Sunoco and DX items.
The seller at that time,thought it originally was meant to be stuck in the soft grassy ground in front of a DX station.
As soon as he described the shape of the 2 stainless steel forks & how far apart they were,I knew right where it was meant to be placed.Each flat fork even has a hole with a cotter pin in them,to prevent the wind from blowing them off the pump.
I agree with Ryan,if you ever see one of em come up for sale,in any design or condition,don't balk at the price,as it most likely will sell to another right away while you're making up your mind.