left hand or right hand fuel tank brackets?

[kanuck]

Was wondeing if there is a difference in brackets for left or right fuel tanks?
I have three sets of brackets that I have located in my collection of stuff, some from trucks I took apart and some from bought projects, but they all seem to be similar pairs.
Seems the front to back on the tank seem to be different, or am I mixing up parts, as I have one about two inches longer then the other, but I figured the brackets from the front to the back on the same tank are different.

Anyone know for sure????

Thanks,