The epilogue is a continuation of the prologue. The placement of these bookends relative to the main narrative is indicated by references to Zakalwe's shaved head and "long hair that isn't there any more", which puts both passages at least after chapter Thirteen, in which the character shaved his head. In an interview, the author explicitly stated that "both the prologue and the epilogue take place after the main action of the book". ("Iain M Banks Q&A". The Guardian. 11 September 2000. Retrieved 26 September 2019.)
Use of Weapons by Iain M Banks, 4 August 2012, The Guardian