Is there a difference in V6 ecotec insulators between the VS-VT one an the VX-VY one?

There is. Please refer to the product descriptions and respective part numbers below:

COLD AIR INTAKE 12MM MANIFOLD INSULATOR 4 HOLDEN VS-VY Part Numbers - MI601 (VS-VT ecotec V6) - MI602 (VX-VY ecotec V6)

COLD AIR INTAKE 25MM MANIFOLD INSULATOR 4 HOLDEN VS-VY Part Numbers - MI613 (VS-VT ecotec V6) - MI614 (VX-VY ecotec V6)