okay first lesson, nothing is diffrent about them, aggy (g) or (t) have the same defense as addy no other changes other than looks and price.. Now (g) stands for
Gold Trimmed(Black, Addy, Rune, Chaps, Wizard can all be g)
Now (t) means
Trimmed, thats just the darker shade,(rune is a light blue) or just grey (agian same armour as before can be t)
How to make, there is no way plain and simple, this is how the Trimming scam works, they offer to "trim" ur armour to either (g) or (t) but they just run off with ur armour
Only way to get if from Clue Scrolls (A.K.A. Treasure Trails)
3 levels 1 is black 2 addy 3 rune
Also for rune there are 3 others than just (g) and (t) these are
Zammorak (Red Trimmed rune armour)
Saradomin (white Trimmed rune armour)
Guthix (Green Trimmed Rune Armour)
These items do not have (g) or (t) like a rune kite (g)/(t) they are simple called a Zammorak/ Saradomin/ Guthix kite