I already built an ar 15 5.56 pistol in a 10.5 length. I lucked out an won an sbr kit, which I put a pistol buffer on,  on GB for a little under $520 shipped awhile back. Of course it has no name parts but the trigger is sweet and it cycles smooth. Yeah I consider myself lucky as I was pretty uninformed until I started reading this forum.
So several months later I am reading this forum and late one night I also watch a youtube video on the honey badger. I then started reading posts on it here and I am like I got to do something like this. I am hooked. So I now have two full uppers in 10.5 length, I know hb is 8", but this is my logic. When I suppress the one I want the total length to be at least 16" so I don't have to have another tax stamp when I put a rifle stock on it. I plan on building the other as pistol to sell as suppressed ready with something like the AAC T 51 flash suppressor. Oh yeah these are 300 blackout 1/8" twist with YHM 10" hand guards.
So I guess what I am asking is this a good idea or have I really missed something. Thanks in advance.

So you're going to permanently attach a suppressor to save $200?  Given the costs involved here, another $200 doesn't sound so bad.

That is where my reasoning was off. I forgot about the barrel having to be 16" permanently to run a gun stock. Duh to many late nights at work. Well it's double stamp time for one weapon for sure. Thanks. Just a noob.

Unless you're going to run a SIG arm brace, & given you're doing the paperwork anyway two stamps won't take any longer.