IMSLP hosts public domain scores. Puccini’s Preludio Sinfonico (published 1882, Puccini died 1924) is public domain in most countries (life+70 years). The score and parts are available for free download on IMSLP under the standard Creative Commons/Public Domain mark.
This is the core of your search. You want the What does "exclusive" mean here? Typically, users searching for this term want the best , complete , or rare edition—not the low-resolution scans.
For nearly a century, the manuscript sat in the Ricordi archives (Puccini’s primary publisher). Unlike his operas, which were printed in thousands of copies, the Preludio Sinfonico remained a niche curiosity. It was performed infrequently, often as a "palate cleanser" between operatic arias at concerts.