Yes, I remember that series of seven volumes, a magnificent, gorgeous production, edited by Melvin Jackson. One of the reasons I was engaged to write a new catalogue of SI's plan collection in 1984 was to make the HAMMS plans individually accessible to people who did not want to pay the hundreds of dollars that publication cost then. Jackson's books had just come out and people were already screaming about the price (although if I have not been a poor student intern, I would happily have paid it).
My memory is that SI held blueprint copies of the original HAMMS drawings, not the drawings themselves, and I also have a memory that there were some small gaps in coverage. I suspect the original drawings are in the National Archives, since they were a product of a depression-era government project under the WPA or something similar.
It may be that making the Jackson books available as PDFs is a more likely avenue to wider distribution, since they should be out of copyright by now. SI's maritime curator has just retired and it is not clear if he will be replaced, so waiting for SI to do something about this seems too leaky a vessel into which one could place much hope.
Fred