Yes, you're right! This drink is exactly the same as a classically proportioned Margarita. It was published in W. J. Tarling's 1937 Cafe Royal Cocktail Book, 16 years before the first written reference to a Margarita. Conjecture suggests that this British recipe was copied by whichever American gave the Margarita its name.
Created in the early 1990s by Julio Bermejo and named after his family's Mexican restaurant and bar in San Francisco, the self-proclaimed “premier tequila bar on earth”. Tomas and Elmy Bermejo set up Tommy’s in 1965 and Julio is one of their five children, all of which are involved in what is truly a family business. Julio has become a legend in the drinks industry for the Tommy’s Margarita and his knowledge of tequila. Tommy’s Margarita now appears on the menus of bars all around the world and in turn, the small family restaurant where the drink was created has become something of a mecca for bartenders and bar flies wanting to experience the now famous drink in the bar where it was invented. Their journey is a well-rewarded. At Tommy’s the classic Margarita trio of tequila, sugar and triple sec is enhanced by using agave syrup in place of the triple sec and the use of hand-squeezed Persian limes. The drink is served accompanied by plentiful tortillas and salsa. The bar’s shelves groan with the largest selection of 100% agave spirit in the USA and drinkers are encouraged to sample how different tequilas taste in the bar’s signature cocktail.
The traditional Margarita recipe is 2 parts tequila, 1 part triple sec and 1 part lime juice. This produces a drink which is a tad on the sour side with the triple sec not quite balancing the lime. We like to add a spoon of agave syrup to boost flavour and improve the drink's balance.