Figured it out. Found a comment on a post in the FreeBSD forum stating that many Dell laptops are shipped with RAID enabled. I picked through the bios to find that setting, voila!, RAID was checked, checked AHCP, saved it, and the disk then showed up in the installer. The installation then proceeded without a problem, and booted into MATE. Makes me wonder if that was the problem with the 7490..??..other Dell buyers beware, but it's a quick fix.
Observations:
1.) Ghost boots MUCH quicker than a regular FreeBSD system. Congratulations to the team!
2.) It seems to take a while for the system to turn on the wifi chip. At first boot, the wifi says it's not enabled, but fiddling with turning networking off and back on, and then looking at the list of available wifi SSID's twice to find mine, which is in the house. Anyway, it's working now.
