I gotta tell you, Apple has some real problems in educating their salespeople. I would just walk into a store but I can't deal with hordes of people, anti-social me. Anyway, the conclusion I came to with the 3rd Apple salesperson that I spoke with on the phone, the other 2 having no clue, was basically what you said, that an A1660/61 should work with any carrier when bought outright. The one thing the could not answer is if my phone would work without activation from Verizon with a T-Mobile sim. I'll just wait until the crowds die down and venture into a store.
Thanks for the very helpful info.