Help identifying two lead component with glass cover and serpentine trace under it
That is an LDR.  A Light-Dependent Resistor.  It is used mostly in voltage-divider circuits that can detect the lowering of resistance in the presence of light.

It is not specific to IR without a filter.

You can wire it like this to detect incident light:



It looks like this wired to an Arduino Uno:



You can get the code and some discussion HERE



LDRs are handy for detecting both light and dark, which means they can be used in circuits that can turn something on when the light goes away, and vice-versa.  

Here is an interesting article that discusses how to do this without a microprocessor:

LDR Circuit Diagram



The OP mentions ordering a pair of IR devices but does not say why.  Note that phototransistors paired with LEDs can be used for much faster switching, like for instance data communications.