New user questions about PhysX and older games

I’m new to game modification and have a question about the Nvidia Gameworks PhysX in relation to the 2006 PC rts game Rise of Legends (ROL) which uses the AGEIA PhysX physics engine, as well as the 2003 PC rts game Rise of Nations (RON) which I couldn’t find any info if it uses PhysX but is a 3D game with some 2D graphics.

Can what is being offered through the Gameworks be used to mod old games such as these two or is all Nvidia offers only for new games made in recent years and/or game developers making new games?

With both games you can import, export, edit and create 3D models (BHA, BH3 files) in 3DSMax and Blender.

So how do the PhysX options in the menu above, as well as Visual FX all the way thru Tools, figure into this?

And is there anything else on the Nvidia Gameworks (or elsewhere if not here) that I might be able to use to mod the graphics, models, etc of the game or do some other things not usually thought of?

Basically I’m trying to find out if there is potential to use the Gameworks to modify these old games to breath some life into them and test some unexplored potential.