My 78 spider came with a solid plastic windshield washer bottle held in by a piece of wire.
I'm pretty sure it's not original as there is no mounting holes for it. I believe the 78's had a bag right?
If so, can anyone tell me how it is mounted? is it the two pieces of metal (hooks?) or some other way?
A picture would be a GREAT help!

Thanks guys!

Its the two little hooks near the front passenger side of the engine bay. Don't got a picture, but its pretty self explanatory. The grommets hang on the hooks

Heres a pic of how mine mounts, hangs on 2 hook in the very front corner on passenger side of the engine bay.

Perfect! thanks for the answer to the mystery and the great photo!