Mark Cross was the first US luxury leather brand. Now, I believe, they are primarily women's purses and accessories. In the disco 80's they were quite chic, probably the era of that men's shearling coat. But that is just a guess.
The coat was high end quality and costed at least $1K during that era. Same type of coat today would be closer to $2K
I don't think they are illegal, but they were rare in the first place. The last one I saw on eBay had none of the adornments you mention yet sold for >$500, so I think you'd be looking at well over $1000 for one with ivory, silver or gold on it.
Ebay Policy overview
Most weapons can't be listed on eBay because of strict federal and state government regulations and international laws banning the sale of these items. Please review the list of items below to find out what you can and can't sell on eBay.
For certain types of weapons that can be listed, sellers have to follow our guidelines, as well as meet the following requirements:
The item is listed only on the eBay US site.
The seller is located in the US
The item is also in the US
The seller offers only domestic shipping for the item, since international shipping would make the item available in countries where it might be prohibited.
The item complies with California law on the sale of weapons.
Hidden or disguised knives such as air gauge knives, belt buckle knives, lipstick case knives, or writing pen knives
Out-the-front (OTF) knives
Push knives—they're also called push daggers, punch daggers, punch knives, push dirks, and T-handled knives
Replica or imitation switchblades
Switchblade knives (knives with a blade that open automatically—for example, by pressing a button or through inertia or gravity) Sword canes
Throwing stars, ninja stars, throwing cards, Batman symbols, or Cyclone knives
So, according to this, sword canes are not allowed on Ebay.