Q:

Could the Stargate Program have stolen a DHD from an uninhabited planet?

In "48 Hours" they destroy the last functioning DHD on Earth in order to save Teal'c, however at the same time they establish at least a rudimentary knowledge about how to hook up and unhook a DHD device. It has also been proven in many other times that they can dial the gate without the DHD.
What stopped them from going to some uninhabited back water world, unhooking the DHD there and bringing it to Earth so that they could have a fully functional DHD?

A:

The SGC in the early days before the Prometheus, they tried to avoid cutting off worlds from the gate network.  Removing a DHD could potentially trap someone who arrived on the world and with no way to effectively survey a world beyond 10 to 15 miles from the gate it wasn't worth the risk.  
As far as gates go, until Prometheus they didn't have a reliable means of interstellar travel that they didn't have to negotiate for.  And I would assume that the Jaffa Rebels and the Tok'ra would both not approve of loaning the SGC a ship to break a part of the gate network.  Everyone seems to be a bit pissed when Anubis does it.
By the time they could gather DHD's they had sufficient knowledge of the gate control systems that they no longer needed one, and their own "MacGyvered" had more precise controls and was resistant to DHD system failures like Baal's DHD virus.  And by the time they built the  McKay-Carter Intergalactic Bridge they had such mastery of the gates no longer needed DHDs.

A:

Early in the SG-1 era, it would have been difficult, as you need a ship to transport the DHD, and until the Prometheus Earth didn't have one.  Once they got the Prometheus and the later, more advanced ships, it became feasible.  However, any time they needed an extra DHD, it was an emergency, so they didn't have time to grab one from a nearby system anyway.
In the late-SG-1/mid-Atlantis era, they should have had a ton of extra DHDs lying around.  After the McKay-Carter Intergalactic Bridge was built, they should have had a maximum of 17 Milky Way DHDs and a maximum of 17 Pegasus Galaxy DHDs sitting in storage somewhere.

A:

Maybe SGC was afraid that it will somewhat break the status quo achieved with Russians. Of course they could just not tell them that they brought the DHD, but I believe Russians would sooner or later know and be angry, because that would mean another advantage of USA Stargate program. Russians could demand restoration of their wormhole travels as a "recompense" or something like that.

