I believe it's a topper for a larger "shelving" type storage unit, instead of the smaller island racks you're probably thinking of. I've only seen the sign offered over the years, not the whole unit. Your's appears to have extra holes drilled in it. My "file photo" of this sign has 6 holes total. The 2 on each side, then the one under each "O" in Mobiloil. You didn't list the size, but if it's about 45" wide and 8" tall then it's the same sign I have in my saved photos. I do not have a pic of one in use.
Yes it is 49" x 8". Thanks for your time and help!