A good question. No, it is not.

Chinese soy sauce, like Japanese shoyu is brewed and fermented. The distinction between "light" and "dark" made on bottles of Chinese soy sauce concerns the length of fermentation time. Generally, a light soy sauce has been brewed for several months and dark soy sauce for as much as three years or even more.

There are now available low sodium varities of shoyu or soy sauce but these state that they are low in salt. If you are on a low sodium diet, Chinese light soy sauce is not for you. And if you want a Chinese light soy sauce, the low sodium brands are not going to deliver the nuances of flavour that you want.

The light and dark of Chinese soy sauce is not as much in the fermentation time as it is in the colour. Light soy is lighter in colour and generally saltier than dark soy. Dark soy has additives such as caramel or molasses to impart a reddish colour to your food (usually meat or tofu) when cooked.

Light soy sauce is in fact saltier than dark soy because it isn't "cut" with additivies.

I should note that light is an unregulated word in the food industry, and can mean anything from low fat to light in colour.