Yes, this is actually a known issue when using the “Bot Warfare” mod (for the Plutonium IW5 project). You’re not alone in seeing weird unlocks in-game.
The mod may be overriding or “spoofing” your weapon levels/unlocks (showing you “unlocked” but not actually toggling the flags/server-side data that allow equip/display of the attachments).
The client-side UI might show the unlocks while the game engine still requires certain server or profile flags to truly allow equipping/displaying them, or there could be a mismatch between the modded environment and the official progression.
What you can try, since you want to unlock them on your own:
Use a clean profile or server. If you don’t mind resetting, try playing without the mod (or disable the mod) for a session and see if your unlocks behave normally. That helps determine if the mod is indeed causing the glitch.
Check mod settings/menu. The Bot Warfare mod has its own menu/DVARs including load-out and rank settings. Maybe there’s a setting that forces “max rank/unlock” behaviour.
Play standard multiplayer/not modded match or switch to a server that doesn’t use the mod to see if attachments/camos show correctly.
Check for updates to the mod. There might be a known bug or a patch (the GitHub lists versions 2.2.0, 2.3.0) which may address unlock/level issues. Or else, contact the mod author or the modding community to see if anyone has a workaround for the issue.