The data in the global legacy files are quoted in the local currency. Here's an example, web query on the company with GVKEY = 25369 (Jardine Lloyd Thompson Group) returns total current asset = 527.385 in the year 2007. This is consistent with the balance sheet statement obtained directly from the company's website (page 45), which is showing currency unit (British Pound '000).
In order to convert everything into USD, you will need to use the Compustat Global Currency file, where you can get a time series of conversion between your local currencies and USD. You can then map the exchange rate back to the financial statement to get the uniform number quoted in USD.