There are no rear rail mount points on our 4u chassis.
There are holes tapped on the sides for installing sliding drawer setup for use in a server type rack, but I don't know of any customers who've taken advantage of this feature yet.
If you do want to purchase the rails, we could special order them for you. Just talk to your sales engineer and we can get you pricing.
20" deep from faceplate to rear.
19" from rack ears to rear.
20.75" from front handles to rear.
They're roughly 20" x 19" x 7"
Weight is about 50lbs for Fedex purposes, but that includes dimensional weight due to the box and packaging.
Physically they're around 40-45 lbs give or take depending on how many hard drives are installed and how much copper cooling is built on the motherboard of the model in question. These values can change a little as those parts are revised.