artcoder,

You've brought up an interesting question, which not alot of people could really come up with a definite answer to.

With purchasing full rights to a pre-made, you have sole discretion on what you do with it. Re-selling it as an "original," when most pre-mades are well-known, loses the trust between you and a potential client, losing all chances of a possible contract.

When I purchased a pre-made template to re-sell when I established my own Web Hosting provider, I let all my clients know it was purchased elsewhere, but I had exclusive rights. They liked the fact I told it as was, and they remained with me for the following three years, until I had to shut down due to issues.