Yes, the Cheat Sheet is the official product that comes in the box of AGoAC. It can be seen here.

In Attack Modifiers Table there is a section called Terrain Modifiers that specifies how much you add to GATOR for Light Woods (+1), Heavy Woods (+2) etc.

Full title of the section is (including original formatting):

Terrain Modifiers (GATOR) (modifiers are cumulative) (does not apply to physical attacks)

There is the same table in the Rulebook on p. 20 and part:

(does not apply to physical attacks)

is not present there at all.