After taking out the motherboard and power supply revealed no obvious problems-- the interior of the machine was squeaky clean and dust-free after 30 years of storage-- I powered it up for the first time.
Everything works perfectly!
The computer came with a Monitor /// in an unopened box, an external Disk ///, and boxes of dealer-oriented material, including AppleFile ///, VisiCalc ///, and AppleWriter ///, with disks and training manuals. There was a box of miscellanea as well which included full manual sets for Apple ][ and Apple /// Pascal, which warmed the cockles of my heart.
The only thing I noticed is that both floppy drives seemed rather loud-- they may obvious scraping noises as they seek, although they seem to work perfectly. Perhaps there's something inside I should lubricate...