I hear some slight differences for the first verse in DSB version:

Some day you'll find the end of my rainbow
When/and maybe you'll find a pot of gold
Some day, while runnin' around, you'll find what we never found
That golden mist
The rainbow's kiss
It all falls down in a little pot of gold

To my ears, your second verse is pretty close to what the Cheap Suits sing. The DSB seem to sing something different, particularly the second time through - closer to what Norman Blake sings in his version on 'Flower From the Fields of Alabama'.

Some day the silver clouds will be lifting
That seem to cover up my gold
There is nothing I can do
While that I am feeling blue
But chase the rainbows in my soul

I don't reckon there can be anything definitive here, unless you can find some sheet music [it sounds like it may have originated as a pop song, but I find nothing at Levy] - you takes your pick.

--Stewie.