I’m mostly joking, but would it be treason? A very high-level of theft?
It definitely not treason. (unless part of larger treason plot).
It’s theft/burglary, and if you looked, you could probably find other federal statutes that would be in play.
I would imagine it would include at a minimum:
Theft of government property
Trespressing on goverment property
10 years max for each count
Aren’t there, like, dozens of them? Is the parchment onto which Jefferson put pen to paper still extant?
The ink on the original, or at least “official” version on display in D.C. is so faded it’s barely legible. It’s a little sad to see. If I remember correctly that’s because it was on display framed on a wall of the patent office building for many years, and large windows nearby let in a lot of damaging natural light.
Now it’s kept on display in a dim room in the Archives building, backlit sightly to make the writing visible as much as possible.
Good answer. That thing is a national treasure, and anybody who nicked it would for sure end up in a cage.
The “original” is the one that people put their ink signatures on. When they went to conserve the one in the archives, they saw that the back actually had on it “The Original Declaration of Independence July 4th 1776.”
The dozens that people remember are the Stone Engravings.
In 1820, the Declaration of Independence was already showing signs of age. Secretary of State John Quincy Adams commissioned printer William J. Stone to make a full-size copperplate engraving. This plate was used to print copies of the Declaration. The 1823 Stone engraving is the most frequently reproduced version of the Declaration.
What did they send to King George?
And more importantly, did they keep the little green registered mail return card? It would be pretty embarrassing at this point to have the UK go “Oh hey, about that Declaration? Yeah, we never got it. Liz said to tell you ‘hi’ and that your Governor-General will be along shortly.”
The signers sent a copy of the Declaration to King George III with only two names on it: John Hancock and Charles Thomson, the President and the Secretary of the Continental Congress. Why? They didn’t want the British to have the names of all those committing treason!
Hah!!
So, it was like:
Signed,
John Hancock
Charles Thomson
. 
More like J*** H****** and C****** T******.
Actually, you’re right. Hancock waved his, um, hancock, right at Georgie.
So, ultimately, only these two really mutually pledged to each other their Lives, their Fortunes, and their sacred Honors?
I wonder if that is still in the British archives?
Or did King George rip it up and flush it down the toilet?
For what it’s worth, treason against the US is very narrowly defined (in the Constitution, no less):
Treason against the United States, shall consist only in levying war against them, or in adhering to their Enemies, giving them Aid and Comfort.
So definitely not treason. Not by itself, anyway.
There is no evidence that a copy was actually sent to Geo III although he did eventually see a copy.
British General William Howe obtained several copies of the Declaration several weeks after it was issued. He sent those back to London. There is no specific recording of the immediate discussions. However, the King had been saying for more than a year that, despite protestations of loyalty, the colonists had been fighting for independence. This Declaration was merely a confirmation of what he already believed. The ministry had already sent the largest military force that had ever crossed the Atlantic, expecting to crush the rebellion. After receiving the Declaration, it simply continued on with those plans.
I should note that, jokes aside, what General Howe probably brought back was the so-called Dunlop broadsheet that was distributed to the troops, the one with only the two names on it.
However, none of them were signed by anybody. The two names were just set in type, with Hancock’s in a larger typesize.
One has to notice how in the last cite you made, the ones transcribing the text of the declaration of independence (louthrustonsar.org) have also a bit of fun by mentioning John Hancock with a larger and bold font. 
While incarcerated he’d be living the life of Reilley.