There are only a few examples of the Amarillo variant known. I've seen the KC Thief bottle in person just once but never an Amarillo example. The Monterey variant is embossed with "Monterey" on the front underneath the main embossing. According to the Dr. Pepper Collectible Bottles book, Monterey might denote the flavor of the soda that the bottle originally contained. This bottle isn't necessarily easy to find but one does pop up on eBay a few times a year or so.I am one of the few who have been able to find a KC Thief (2 whole, 1 half bottle). The two whole ones are ice blue and aqua green. I traded the aqua green one to a friend who had a couple of amber Kansas City amber Coca Cola straight sides (circa 1902-1909) and I kept the ice blue one. I sold the 1/2 Thief to Ray D. in Texas, who intended (as he told me...) to play a trick on a friend.
Anyway, I have never hear of an Amarillo Thief bottle, let alone a Monterey (Mexico?) variant. When you say "script"what do you mean? When you say "1906" what do you mean? My understanding was that the KC Theif I have, was produced in 1905-06 so, that reference has significance to me.