Are these useful or should they end up in the garbage?

[87Skier]

Not looking to sell these, just curious if they are good or should end up in the garbage.

These are extra fuel tanks that mount where the rocker boxes should be. The PO cut the boxes out to put these in. When I got it the whole fuel system was shot, so I pulled these to clean up everything. As far as I can tell, these each hold 15 gallons. These had a fuel cap in front of each rear tire.

I like the idea of having the additional fuel storage, but these require cutting the rocker boxes. So, do these belong on someone's truck or in the garbage?