In the 8052AH the you and I can buy it is the basic52 interpreter. In the case where you wanted 50,000 micros with your code in it, you would pay Intel to make them with your code - this was called the 'mask program'. Nowadays, it's probably cheaper using a flash part even for large quantities.

If you want more info on basic52 - do a search on 'basic52'.

As you probably know - Intel don't make 8052AH anymore but Micromint did their own version using a 80c52. Today you can just flash the basic52 into a number of flash based 8051 variants.