Please identify if these pieces are part of a set, medium grey and red Technic bricks with a window I have these pieces, constructed a shown, that were given to me in a pile. Is this part of a set or something someone just build?
At first glance it looks like something out of Model Team set, like one of the trailers. 

There are two types of standard Technic pins, black friction pins and grey frictionless pins. 

Black friction pins are used to build strong connections and grey frictionless pins have low friction and allow parts to spin easily.

It seems odd that the two pins connecting the Technic bricks as shown below use grey frictionless pins as I have never seen an official LEGO set that wouldn't use black friction pins for this case.



The window also stands out as an odd feature in this build.