The number and layout of the cabinet side conduit is distinctive. V3 cabinets are connected to 4 stalls and urban supercharger cabinets, as a form of V2 supercharger, are connected to 2 stalls. So, even if you can't recognize the differences, you can compare the number of cabinet positions to the number of stall positions. If those are in a ratio of 1:4, then it's a V3 site. If the ratio is 1:2, then it's a V2 site.
In otter's bottom picture above, ignore the grouping of conduit on the left as that will be for power distribution and control. The 5 locations to the right will be for V3 cabinets. To compare that to what a V2 pad looks like, here's a picture from South SF, CA that shows the conduit stubs for the 10 V2 cabinets. You can immediately see that the layouts are very different.
In otter's bottom picture above, ignore the grouping of conduit on the left as that will be for power distribution and control. The 5 locations to the right will be for V3 cabinets. To compare that to what a V2 pad looks like, here's a picture from South SF, CA that shows the conduit stubs for the 10 V2 cabinets. You can immediately see that the layouts are very different.