Since Season 8 brings back metal detecting mission introduced in Season 1, you "need" to use the Metal Detector Module in those new missions. However to be able to install it, you first need to unlock it on Imandra map, which can be only accessed when another DLC is bought or via co-op, not an ideal position to put players in, especially when they want to only focus on Season 8.
Belozersk offers no ways of acquiring Metal Detector Module other than doing another region for that, so I'd propose to have additional contract before any of the metal detecting starts to give player as a reward a Metal Detector Module, similarly as the Don had alternative way of acquiring Prototype Exploration Unit.
sidenote: Ford F-750 would really use to have the detector on its back, just saying