OK, did you buy it from the PARD website?
If you look into the IR (IR switched off!!!!) and and adjust the focus, you should, at some point, be able to see the surface of the device that's producing the IR
If it's a vcsel there will be a very small gold coloured square with 2-5 very thin wires running into one side of the square
If it's an LED, it's much bigger, no wires are visible but there will appear to be a series of dark bars running across the emitter , usually with a gold wire running down the centre at right angles to the dark bars. You should also be able to see that there is a dome shaped lens on top of the LED surface
Cheers
Bruce