I tried my L2 tailcap on my L1, and although it's slightly loose fitting, it does work properly.
Now let's try it on my A2 and see what happens...BRB...OK, works on that too, but once again, it's slightly loose fitting.
Both flashlights appear to work the same as they did before.
But this is a subjective opinion; I did not meter either one for "before" and "after" analyses.