Eh, yes and no.
When the Aerospace Metals Division of SAE agreed to take responsibility for many abandoned military specifications, the great majority were translated essentially word-for-word into AMS documents. Hence for example Mil-F-7190 on forging became AMS-F-7190 with essentially no change except formatting. Not quite so with Mil-H-6875, which covered heat treating of steel, both raw material (as done by steel mills and forge shops) and parts (done by heat treat shops).
When picked up by AMD, the scope paragraph was changed to note that AMS-H-6875 would apply only to raw material, and parts would be done in accordance with the AMS 2759 series of specifications. Paragraph 3.4 of AMS-H-6875 defines what is considered a part. So if you're looking to heat treat a part, you'd use the appropriate AMS 2759 document, of which there are currently 11: the base and /1 through /10, with /11 on stress relieving being in the works. These can be ordered direct from SAE, if you don't feel the need to pay Global's markup.
Yet my take on arnoldh's original comment was that it referred to the heat treat condition of Mil-Handbook-5 (now MMPDS) materials. I believe IsraelKK's direction to download the old, superceded document from ASSIST was right and proper, as the heat treat condition is adequately, and accurately, spelled out in that document. Yes, there have been updates- the most recent edition of AMS 2759/5, for example, no longer requires dipping 440C in water after the quench. Yet if the goal is to understand MMPDS material properties, the reading the cancelled Mil-H-6875 (and Mil-H-6088 for aluminum alloys) will do nicely. And you can't beat the price.