WF-500 Xenon Lens Diameter

Was wondering if anyone could give me an accurate measurement of the lens diameter on the Ultrafire WF-500 Xenon flashlight.
I am ordering one from DealExtreme and plan to purchase an aspheric lens and will figure a way to replace it.
My guess is that I need a 50mm lens. Can anyone confirm?
Also is the original lens plastic and glued in? I am just trying to figure what I will have to do to get it out of there.

I am ultimately seeking a tighter throw for the light as I will be refashioning the head to add not only the lens
(linked here: http://dx.com/p/50mm-optical-glass-lens-for-flashlight-spot-light-44653 )

But also plan to add a glass camera quality IR filter for night vision hence the xenon bulb as white LEDs do not emit IR radiation.

Thanks and any further suggestions?

I guess this is a bit late, but yeah it got a 50mm lens. Drops right out when you open it up.

However, afaik normal incans don't work very well with aspheric lenses. Something about the smaller light emitting surface of leds makes them work better with aspheric lenses than incans.
Most of the finished aspheric lights at DX also seem to have some mechanism for adjusting the distance between the led and the lens (similar to the focus thingy on maglights).
I can not see doing that (adjusting the distance) in any way with the WF-500.