Fuel tank replacement

I'm in the process of replacing the fuel tank on my 99 K1500. I have a new fuel pump module, but need to switch the two plastic breather (vent?) units from the old tank to the new tank. Before I ruin the old units I need to ask how they are removed from the tank? Anyone ever dealt with this?

Are they solid plastic to tank?

Or is there a rubber grommet in tank for them?

Is solid plastic to tank you can no switch them.