I'm by no means an expert in this regard, but, personally, I wouldn't worry. I have a TP-Link Archer C7 v2 for years now and that doesn't have any shielding around it's radios or SoC by design, for instance. So, I wouldn't assume that the shielding is crucial. I would rather check how the device performs and if that is satisfactory, I'd keep the device and use it.
You can check the FCC certification photos at, for example, https://fccid.io/2AFZZR4A (assuming that is your model).
On a device certified with shields but then missing them, it potentially may cause interference with other devices, and/or be more sensitive to interference from other devices.
thanks, I got a bit ahead of myself and put openwrt on it already. I'd have to look into reverting it to send it back
I might just test it some more first.