Yeah, they're G1 prototypes. The big truck in front of Bruticus is a mock-up for Onslaught, and I'd assume the other military vehicles with him are early concepts for the other Combaticons. The bikes look like a step-by-step example of how they get from the first idea of a figure to the final product. The two animals look like mock-ups for Catilla and Chainclaw, I'd guess the blue buggy is an early Fizzle and the orange jeep an early Swindle, next to them you've got resin prototypes of Blades, First Aid and Wildrider, and the jets would probably be early Aerialbots. The green vehicles look like those Micromaster combiner concepts seen in the Generations deluxe book.

Most of that's educated guesswork, take it how you will.