The cuts are sawcuts to show that the book was remaindered, meaning it didn't sell all copies when first published and excess copies were sold to remainder shops like Banana Books.

The 'pulp' stamp could be anything. Possibly it was one of a number of copies destined to be pulped for one reason or another and rescued by someone.

. ------------------------------------------------------------------------------------------------------------------------------------------------------Whomever you may murder, there's no police like Holmes.
Σ Ψ Δ
σ ψ δ
------------------------------------------------------------------------------------------------------------------------------------------------------Whomever you may murder, there's no police like Holmes.
Σ Ψ Δ
σ ψ δ