Well, the real original OM cases were black leather with fine felt linings and a tripod thumbscrew. They also had a chrome nameplate mounted to the front. I have about 5 of them.
There were also brown and tan leather cases offered. I haven't seen one to compare to the black version.
The vinyl cases came out much later, for the OM10 and 'consumer' grade models. Last year I found 4 new-in-the-box of these for about $14 each. They are nice and offer protection but, as Tim points out, are not very substantial.