An Uncorrected Page Proof is a specific use type bound galley.
Uncorrected Page Proof(s), are bound galleys that are Uncorrected, in Page Proof format,
and are not the finished product, and require further work before publishing.
Many years ago, the first use of uncorrected page proofs was used by a competitor of Crane.
Since bound galleys were Cranes, and Cranes were produced by Crane Duplicating it was difficult for vendors to sell bound galleys to publishers.
So the competitors created the term uncorrected page proofs to mean a bound galley.
Ever since it has been used in the trade to present bound galley materials and has confused the market place.