I'm so sorry you're having difficulty attaching the photos.
The trick is to be logged in to JustAnswer.com, go to "My Questions" and to correspond with me from the website rather from your email. That way you should be able to click on the paperclip icon to attach any photos that are in your computer.
However, to save you all that trouble, just let me know the title to each of the prints you have -read off the names of the bird(s) in the legend at the bottom- and I'll be able to give you a value (assuming average condition, no foxing, fading, staining or damage etc).
Now that I've read the "Certificate of Provenance" document you sent -thanks so much for doing that- I've been able to track down general details of this sale in 1987 (and the catalogue that was published about it) but no specifics about individual lots.
There was a lot of hype over the sale at the time, I've been reading, with all the wealthy elite of the day such as Paul Keating, Robert Holmes a Court, John Elliott, Laurie Connell, Warren Anderson and so on, in something of a feeding frenzy to get their hands on these prints, and prices were pushed way higher than they had ever been for Goulds, and they were already expensive. It's not clear how the Dutch born Mr Hank Ebes, the flamboyant former crop duster pilot, owner of Douwma Gallery, Melbourne, got to be the agent for this sale, but he made a fortune selling them.
Gould prints, especially the Australian ones, have held their value nicely through the years, but may not be much higher than those 1987 values.
I have always been a huge fan of Gould. My grandfather had a complete set of both A Monograph of the Trochilidae (Humming-Birds), all six volumes of it, and also The Birds of Great Britain. As children, under his eagle-eyed supervision, we were allowed carefully to turn the tissue paper covering each brilliant illustration -he explained that his fingers were too old and scratchy to do it himself- while he turned the main pages. I am also extremely grateful to Gould, and of course my grandfather, as the sale of these after he died helped pay for my education.
Since then I've managed to collect back a few prints I've found here and there, including one from the The Birds of Australia, a Rhipidura rufifrons (the rufous fantail) which I bought at an estate sale here in the US for a 'steal' of US$25 because nobody knew what it was.