Let me give you the ethical answer; Build the bike as it was. Not as something else that it was close to.

Think about you buying something from somebody and thinking you got just what you wanted.
Only to find out it was just close, or made by, or anything except what you bought!

You would not like it so much then. So when you contact the seller, he says it's just like and made by....

You would hit the roof!

Is that clear enough?