pjeski is correct. Unless there is an Alabama law (which I highly doubt, given its political leanings as a state generally) that governs making firearms or registration of pistols, then you don't have to do anything special.
Under federal law, it's legal for an individual to make a firearm for their own use, whether it's a pistol or a rifle or a shotgun. As long as it doesn't fall under the NFA (i.e. short-barreled rifle), there are no registration or marking requirements.
You don't have to mark it in any way as a pistol. You don't have to mark with it your name, address, town, etc. You don't have to create and mark it with a serial number. No marking requirements at all.
It MUST be made for personal use. If you make it with the intent to sell it, you must be registered as a manufacturer with the ATF. But if you make it for personal use, and then later decide to sell it for whatever reason, that's not illegal. If you do decide to sell it, the ATF suggests that you create a serial number and mark it with one, but that's not a legal requirement either.
Hope that information helps.
Aaron