Congratulations, looks like a nice Whirlwind.

ipdb.org if you need a copy of the machine manual
Make sure all the connectors in the cabinet and backbox are seated properly and not burnt, and take a good look at the soldered connections for any loose wires or other problems
pinrepair.com to help figure out issue with ball lock
pinballlife.com for new power cord and flipper rebuild kit (cheap and worth having even if they don't need it right now)
cometpinball.com for led's; 1 or 2 SMD frosted white bulbs would be way better for playfield and most of the backbox lighting
Make sure it's level and pitched properly - makes a big difference to game play
Start figuring out where you're going to put more machines