Get a hoya, b+w, kenko. Just stay far far away from a Vitacon. It is very cheapo quality and the salesman is probably trying to sell it to you for $30 or something. It is worth about $10 max. But give it to me free and I will not even take it.
Are you going to believe everything the salesman tells you? FYI, the "Nikon" tripods are usually cheap freebies, and the Vitacon filters are just cr@p glass. Only go to the reputable shops that we have listed over and over again here already in the consumers corner.
The average sales person is the very last person you should ask what to buy. There are only a few who have the decency to recommend fairly and quote a decent price. In this forum you can a Mass Sales ection with various quotes for different filters, Vitacon is not among them. Have a good reading, see the prices and make up your mind what you really need. No point slapping a piece of glass on your lens just because of the vague panic feeling "must protect". Fear is never a good adviser.
Please read up about filters and the topic of protection. Being careful costs less then a filter, a lens hood offers the same protection and more.
Regarding your viewfinder: I'm not sure whether this component is available as spare part. Are you really talking about the viewfinder or something else?