The D620's should be a core 2 duo 1.8-2.1 GHZ

60-160 GB Sata HD
15" or so LCD

either a 6 or 9 cell (Extended life) battery

620's were almost primarily Windows XP Licensed machines but some could have been bought with Vista (early release, id suggest putting xp on these).

1-2 GB of ram is also a standard config.

Also, IIRC the 620's had integrated video (Intel GMA).

So...Unless these were special ordered... You are probably Looking at

Core 2 Duo 1.86 GHz
2 GB Ram
80-160 GB HD
Windows Xp License
AC Adapter

These make a Solid Web/office laptop.

Dan,
You can delete this if you want, just tossing out some info on the 620's