Using the Config Viewer, which may be accessed through the escape menu, the various attributes of config classes may be viewed.

So far as I am aware, the class of the Virtual Arsenal appears to be 'RscDisplayArsenal'. Unfortunately, Bohemia do not appear to have set an IDD for Virtual Arsenal, and therefore it must be referenced through alternative means. I have recently found that, in a script, the code "uiNamespace getVariable 'RscDisplayArsenal'" should return the display of the Virtual Arsenal. Combining this with the isNull command should yield the results you seek, and it should be possible to employ other commands that concern displays and controls.