Roger LS 3/5A

i thought most of them that i seen on the net are walnut or wood color rather than black

I had a roger ls 3/5a walnut which i bought new in 1989 and sold in 1990 as i do not have a decent amp at that time to connect to and i was conned by one of the hifi shop to trade in. When i went back to the shop the next day it was gone. I regreted ever since and by chance recently i managed to buy a black one from a guy, who got them around 84 or 85.As i paid quite a lot of money for it and hoping it is not a copied version as i do not want to open the cabinet to check for genuine parts. Speakers looked tightly screwed and sealed.

I understand now. The emphasis on the black finish. I profess my ignorance there. You are correct though thinking most if not all seemed to have dark wood finishes. That said, people do have special finishes made or refinish to match etc..

As i paid quite a lot of money for it and hoping it is not a copied version as i do not want to open the cabinet to check for genuine parts.

It depends on the seller really as the speaker may have gone through several owners. You can always ask the seller if the speakers are modified internally in any way. If the seller was not the 1st owner, he wouldn't know himself unless he opens up the cabinet to have a look, that if he knows how to detect the modifications. That is one reason some people prefer to buy new than used. Usually old gear or speakers more than 20 years tend to be more prone to repairs or modifications, some earlier.

Some work on vintage speakers may be required as a matter of course. If someone has put in quality same spec new capacitors you should't be too unhappy.
There has to be some forum, on some audio site, who is really expert, to talk to. These are very popular and desirable speakers. I would search the internet for who is discussing it intellegently.