When the people first boarded the Sleeper ships they were in a rush, because of the ongoing war.
I verymuch doubt Antique cars would've been put onto the sleeper ships because they would've:
1: Taken up too much space.
2: Would'nt have been a neccesity
Thats my opinion.
Would certainly be a reason for no antiques in 1 A.S.
But it's what, 800-something now?
Antiques? Sure. Civilian vehicles? Sure.
You want to haul classic hovercars, you go right ahead, but right now they're Luxury Consumer Goods, maybe in the next version you can say they're antiques or civilian vehicles.
The commodities are made to be excremely general in most of the cases. So you know, candies really fall into food rations and excrements fall into fertilisers probably.
We even have people merchandise pretty much filling in all category of folks traveling in space (except perhaps, land troopers and something to categorize just normal folks)
Now antique car, I really don't see why. Luxury goods, or something like that.
New commodities add a HUGE load of work for the people responsible for the trading system. It isn't just about balancing prices for this new commodity, it also needs to be checked with all others to ensure it doesn't create some unbalanced route. There most probably won't be many more new commodities. Of course there may be some, but there should be significant grounds for them.
I'm not responsible for that area so this isn't definite in this case, but I'm confident in this statement.