Our store didn't have slides.
In November, I called the tech support line and tried to place an order for slides. The very heavily accented Indian on the other end was scandalized that I didn't have a part number for the slides. He was insistent that there should be a listing of parts in the manual for the top chest that identified which part I wanted (obviously there wasn't). He eventually read the names of all the parts he could order for the top chest and one of them sounded close enough that I bought some. He couldn't tell me if "qty 1" was a pair or a single slide. I wanted 2 more pairs, so I ordered 4 just in case they were individual.
I eventually gave up on ever receiving them as the "4-8 weeks" passed without any sliders.
However, today, more than 14 weeks after the initial order, the FedEx man showed up when I wasn't expecting him. To my shock and awe, the box contained 8 brand new ball bearing sliders that fit my tool box!
The receipt isn't very helpful. I shows "QTY 4", so obviously these things are sold by the pair since I have 8 of them sitting here. There's no part number per se, but there's a line that says "ITEM SKU: 92099 ITEM DESC: TOP CHEST FOR 90320 ROLL CAB - VENDOR PART 07 DESCRIPTION 16" RAIL SLIDE". I'm guessing that the "PART 07" for Item 92099 is what you'd need to tell the guy on the phone if you want to order these too.
Since the drawers can be moved between the top chest and the roller cab, it's reasonable to assume the sliders can do the same. Probably.
Now I'm going to try to order an extra drawer because I want all shallow drawers on the narrow right hand column of the top chest.