It's not really possible with the GI Joe tanks.
Every single one of the Collab tanks, except for the tier IX T54E2, is a unique model for a vehicle exclusive to the GI Joe IP with no historical counterpart. This means an unskinned version is impossible.
The Mauler is broadly based on the HSTV/L and the CAT/Mobat is based on the MBT-70/XM803. Those could be added unskinned, but would look visually different and play different