Does anyone know the actual weight of late 2015 27" iMac with built in VESA mount? I was only able to find the weight of the edition with the stand, to match the monitor arms. The arms I'm looking at are up to 17.5lbs or more than 17.5lbs. It should be right around that weight with the VESA mount versus stand, but am not sure if it's on the + or - side. Thanks!