No, although many people from the English-speaking world and young people anywhere would think so. In reality, measures and scales have been tightly controlled ever since antiquity. In Athens, a seller who was caught cheating by the inspector not only lost the goods but had his scales destroyed too. Each each country (or even city) had it's own measures. If the European countries hadn't converted to the metric system, there would still be the Swedish pound (skålpund = 425g), the Norwegian pound (pund = 498g), French pound (livré = 489.5g), Russian pound (funt = 409.5g) and so on.
From: http://www.unc.edu/~rowlett/units/
livre
a traditional unit of weight in French speaking countries and in Greece. The livre corresponds to the English pound and to the Spanish libra (see above). The livre is divided into 2 marcs or into 16 onces. The French livre varied from market to market, but the official standard from about 1350 to the introduction of the metric system was the livre poids de marc or livre de Paris of 489.5 grams (1.079 English pounds). In modern France, the livre is used as a metric unit equal to exactly 500 grams or 0.5 kilogram (1.1023 pounds). The traditional Greek livre is also about 500 grams.
Notice, that it was the livre de Paris that was 489.5 g, and even though this was the standard since 1350, the livre did vary from "market to market", meaning enforcement was lite.
I'm sure that had the metric system not come along when it did, some international agreement would have set a "standard" for a pound unit.
Another unit that varied all over the place was the foot, and it was said that their were over 5000 variations at the time of the invention of the metric system in the 1790s.
I'm sure there was a pied de Paris too, but it also must not have been enforced universally.
