How to get the old units..

How would one get the old units from ROC that were replaced in TFT. Im specificaly talking about the Catapult which is now the demolisher and the siege weapon the NE had which has been replaced by the Glaive thrower. I think there might be more but i can't really be sure. So how would one get to those units?

If it has something to do with extracting things with MPQ or what ever it is could you please show me a tutorial of how to do it or tell me?

Thanks.

If you directly alter the demolisher and glaive thrower or copy their model field data directly to another unit, the field immediately below it will be something like "Alternate versions".
Set it to "Reign of Chaos" instead of "Frozen Throne".
This also works for the Alliance's Priest, Sorceress, and Siege Engine. Most of the other model changes are pretty insignificant.

Ah yes i see it now, thanks.