I think everyone has cleared up your first concern… HDSL2 is 2-wires in… 4-wires out. Wired output is RJ-48X or RJ-48C as with any other T1 being delivered.
For the housings… There are a couple different mechanics (physical demission and pin-out) of NIU (smart-jack) enclosures that are used. Far and away most common is the T200/400 mechanic housings or shelves. It would be a pretty safe bet they’re going to be using a T200/400 sized H2TU-R unit.
I don’t think doing all that pre-work would be necessary… Placing a “demarc here†sticker and ensuring the order was placed with Verizon with proper address and suite number should all that is needed.
Take a look at the couple of the most common manufactures web-sites for more specific information.
www.adtran.com Adtran 2-slot housing is part # 1242034L3
Adtran 14-slot 23-in rack mount is part # 1150092L1
www.Westell.com (Westell purchased HyperEdge)
HyperEdge 4-slotis part # DTWA-528-04-I2L4