Identify this bumper?

I was a the Rolling Bones run last month and an old timer had this bumper. He said he kept hitting something with his lawnmower, so he started to dig and this is what came up. I've looked in all of my books and can't find anything like it. Anyone recognize this?

 

could it be one those "rubber baby buggy bumpers"

 

it's supposed to be that shape? looks lopsided
dan

 

any number of makers back in the modelt and a and little later making bumpers to keep pedestrians safe, many many goofy cow catchers, might never know who did this one