When we last ate there a couple of years ago we sat at one of the regular tables near the back. I don't recall if they had any which seat more then 4 people. If those aren't attached to the floor, they may be able to push 2 tables together. We didn't care to sit in those cars and have to talk to the back of the heads of others in our party.
We’ve eaten there probably 40 or more times over 30 years. The only time I’ve ever seen 3 is when it’s parents with a very little one. There’s no way 3 adults or even 3 school age kids would fit in a row. You’ll be good, they have you in 3 rows.
I'm pretty sure all of the cars are designed with 3 rows of seats that fit 2 adults per row. Sometimes we'll see parents with a toddler seated together, but 3 adults wouldn't fit.
The only "cars" that have a different configuration are the ones with just a front and a back of a car with a table in between to seat larger groups across from each other. There are some 4 top tables in the back that a previous poster mentioned, but we've been told they are for walk ins.