Document names and proper nouns/definite articles

While I wouldn't dare to say that this is a 'rule', I would say that the definite article the is generally used before mass / uncountable nouns when you are referring to a specific instance of that noun.

In your example, you are referring to the Inventory and stock list amount, rather than, say, the purchase amount, or the sales amount, or the amount of your salary.

Similarly, you might say:

The twenty people on the course - as distinct from people in general (no article), or the millions of people not on the course.
The hospital staff - as distinct from The university staff
The river water - as distinct from water in general (no article), or from The lake water.