dang3rousdave -- Welcome to pinball, Pinside, and Aerosmith!
I don't know where previous code releases can be had, and I don't know why you would want them.
I've not tried a line out of a machine as yet, but I wouldn't be surprised if it's not studio quality like you're accustomed to dealing with.
I've not been much help, I know. But didn't want you to think you're being ignored. Most folks here on Pinside are pretty friendly.