Does the GRB rack bags have front & rear rack rails?

GRB-4U is a standard 4U audio rack bag. The GRB bags have front rack rails only.

The GRB rack bags are portable, light weight options to protect your rack mountable equipment. These are available in 2U, 3 U, & 4U rack sizes. These have a 14” depth designed to hold shallow mounted gear and are made with 9mm plywood interior frame. The outside is covered by padded nylon, has front & rear zippered access flaps, and comes with a removeable/adjustable shoulder strap. The interior is carpet lined.

We do have 4U tapped rack rails as a replacement part = PART-RR-4U

PART-RR-4U – Rack Rails – Gator Shop (gatorco.com)