Xbee Randge Enclosed in ABS

If the series 1 pro gets 1mile range outdoors LOS, what would its range be enclosed inside ABS plastic, would it be degraded down to its indoor range of 300ft? What if it was communicating with another device also inside an ABS plastic enclosure? Would the effect be compounded in anyway?

ABS plastic is transparent to RF signals so the range would be the outdoor LOS range.