I'll have to say that although there are bad sellers on eBay, there are also a large number of very honest and trustworthy ones also. Especially those that sell new knives. I think some of them also have brick and mortar stores and are extremly reliable. It's true that many don't take their own pictures and use stock photos, but I can understand that when you list and stock hundreds of the same model. Buck does the same thing. The pictures you see on their website and in their catalogs are a representation of the knife you'll receive, but not the exact one. As with many things, slight variation in color and markings on handles are to be expected and if you can't live with that, you shouldn't buy online unless the seller shows the exact knife you're getting in good clear photos.. Even then, lighting and different cameras show colors differently and even your computer monitor setting can affect the color you "see".
If, for instance you order a stag (elk or sambar) or Koa Flamewood handled Buck from their custom shop or one of the many Limited Editions, don't expect it to look just like the illustration because 99% of the time it won't. I can testify to that, I've ordered and received both and neither one came close to looking like what the site showed. Same with the Elk handled cutlery set I bought, they are nice, but they used their "best" antler on the set they used for illustration and not on the set I got.
I've bought literally hundreds of Bucks, new and used on eBay and only once did I get a fake that I didn't KNOW was a fake before buying it. Just do your research (which you are doing here) and you should be fine. It also helps to be a member of the yBuck Collectors Club so you have access to all the catalogs. If you see a "Buck" knife you like online, you can look to see if it is in the catalogs. If it isn't, that's one indication that it MAY be a fake. There's a lot of "models" out there in fake Buck boxes and with Bucks name on them that don't even resemble anything Buck makes or has made in the past.