OK. Here's an overview of the different phases of Viewliner paint schemes and body styles. I am not an Amtrak expert, but nobody else has put forth a nice comparison so I will attempt to. If I get anything wrong, let me know and I will change it, but this is what I know to be correct.
Body Styles:
Viewliner I- built in 1995-1996, these primarily consist of 50 sleepers. There were a couple oddballs including a diner (Indianapolis) and some observation cars, but this production was basically just sleepers. Some of the sleepers have names in the River series (ie Croton River, Mississippi River, etc) while most are currently unnamed. These cars are distinguished by the exposed underbody equipment.
Viewliner II- built 2012-present, the first of this order seen were baggage cars to replace the heritage equipment. These baggage cars arrived in 2014 and 2015. The next to arrive were the diners which are all named after cities (ie Boston, Augusta, etc). The diners were delivered 2016-2019. In 2019, new baggage/crew dormitory combo cars were delivered for select trains including the Crescent. These cars alot roughly 60% of the space for crew quarters, freeing up a lot of room for paying passengers in the sleepers, but at the expense of much needed luggage space. New sleepers should be coming soon as production continues, but the entire order of Viewliner II's was supposed to be delivered by 2015. Viewliner II's are distinguished by the skirting that covers the underbody equipment.
Paint Schemes:
Phase III- Introduced in 1976, what the Viewliner I's were originally delivered in. Large, equidistant red, white, and blue stripes. The Viewliner I's also had large Viewliner script lettering and small block Amtrak lettering. The new Viewliner II equipment has all been delivered in a modified version of this scheme with the addition of a red reflective stripe at the bottom of the car per FRA requirements and use of the "Amtrak America" Travel Mark logo.
Phase IV- Introduced in 1993, featuring a massive blue stripe with small red and white stripes on top. Has bold Amtrak lettering in block text.
Phase VI- Introduced in 2002 and currently worn by all Amfleets, Superliners and Viewliner I cars. Most railfans call this IVb because the only major difference is the use of the Travel Mark logo rather than bold Amtrak text.
Below are photos with captions noting the body style and paint scheme. I don't have photos of all paint schemes so you'll just have to use Google for info on those. I hope this is helpful and clears up the confusion!
Left: Viewliner II Baggage in Phase III paint, Right: Viewliner I sleeper in Phase VI paint
Viewliner II Diner in Phase III paint
Viewliner I Sleeper in Phase VI paint
Viewliner II Baggage in Phase III paint
Viewliner I Sleeper (Croton River) in Phase VI paint
Left two: Viewliner I Sleepers in Phase VI paint, Right: Viewliner II Diner in Phase III paint
Left: Viewliner II Diner in Phase III paint, Right Three: Viewliner I Sleepers in Phase VI paint
Left: Viewliner I Sleeper in Phase VI paint, Right: Viewliner II Baggage in Phase III paint
Viewliner II Bag Dorm in Phase III paint
Viewliner II Bag Dorm in Phase III paint