The icon (e.g Apex icon) in Arsenal does not mean that that you need Apex to use this content, only that it was added //with // Apex.
A confusion can follow and it does not help creating "Apex-free" missions.
The [[ https://community.bistudio.com/wiki/Arma_3_DLC_Restrictions | Arma 3 DLC Restrictions ]] page lists the issue well:
"Worse", the weapon **launch_MRAWS_olive_rail_F** has Tanks DLC icon, but is usable by base-game only owners.
Headgear **H_Tank_black_F** can be used, while **U_Tank_green_F** cannot - and there is no in-game notice about it.
As for the request:
An easy fix would be to add an icon next to the DLC icon to all Premium assets (e.g a star ⭐).
A "costlier" version would be to add a closed lock icon (🔒) to the non-owned Premium asset, and an open lock icon (🔓) to the owned ones.
See also: [[ https://community.bistudio.com/wiki/getAssetDLCInfo | getAssetDLCInfo ]]