Gimme one of them fake guns made by Hershel House or Allen Martin or Steve Zihn or Don Bruton or that fella up in Alaska please!
Yep.
Doing it well is a skill.
If a gun is supposed to look like an 18th c. piece, the skill also includes understanding the techniques and philosophy of 18th c. builders. You cannot take a "perfect" (in quotation marks) rifle as many builders on here try to build (every surface polished, every screw perfectly centered, screw slots perfectly centered and all perfectly timed, etc.) and then convincingly make it look old. In that regard, I can't help but to agree with Hugh T.
On the other hand, there are several craftsmen who truly understand the 18th c. rifle, and they can build one that looks like it was just recently found and cleaned up a little, including having all the 18th c. marks of a hand-built piece. That, in my opinion, is a big step above building a "perfect" gun. I'm not talking about hiding poor craftsmanship. I guess some guys try to do that as well. But there are fine craftsmen (including Jud Brennan in Alaska) who aren't slouches trying to hide poor craftsmanship.
A friend of mine calls guns like I am describing "forgeries". I find that disappointing. If the builder signs his name to the rifle and dates it somewhere (whether on the barrel or inside the box) and, moreover, stands behind it at the table as his potential customers look at his/her work and make their orders, then it's not forgery. It's art.