Identify the exact weapon and unlock route before spending time on progression.
The Black Ops 7 progression guide distinguishes base attachments earned through weapon levels, seasonal and weekly rewards, and weapon-specific Prestige Attachments. The guide says eligible weapons unlock their Prestige Attachment after reaching maximum weapon level and entering Weapon Prestige.
Use that as a reference for the named weapon family, not as a promise about every integrated Warzone weapon. Read the current in-game challenge and Armory text, because integration and seasonal availability can change. Blueprints, camos and base weapon unlocks are different rewards.
Artwork: Call of Duty / Activision. Source links below.