I think it would be cool.
To answer some of your previous questions..
BTDT= Been there, done that. I was referring to having used someone else's machine shop to build a firearm. I work in a machine shop.
G-job or "Government job" is machine shop slang for a personal project done on your own time using the company's machines.
A custom 1911 would not have to be registered with BATFE, since it's not regulated under the National Firearms Act of 1934.
On a non-NFA firearm that you build for yourself, I believe BATFE recommends that you serial number it, but doesn't require it unless you decide to sell it at a later date. I may be FOS on that point.
As has been stated, you can use whatever serial number you want.