This looks like the right kind of camouflage to capture Confederate soldiers.
But is that how that was done? How else did soldiers conduct covert ops in the Civil War era?
Even back then, Law of War provided full protection of uniformed "scouts," but non-uniformed or otherwise disguised personnel are not protected. If you were caught doing intelligence activities and weren't on overt status, there was nothing stopping the immediate execution of the "spy."
For this reason, officers on both sides unofficially ran agents and supported irregulars rather than compromise their own legal status. On the Union side you had irregulars like the Jayhawkers of "Bloody Kansas" fame, Tinker Dave Beaty's Independent Scouts in TN and KY, and the Red Strings "Heroes of America" in NC. All of which were derided as murderous bandits contemporaneously, especially under monikers of "Bushwhackers" and "Buffalos." In their defense, they spent much of their time fighting equally murdeous Confederate-aligned bandits. The Red Strings in particular persisted during Reconstruction to fight the original Klu Klux Klan.
The Loudoun Rangers, Blazer's Scouts, the Jessie Scouts were some interesting legally gray units commissioned by the Union. Blazer's Scouts, commissioned to counter Mosby's Raiders, were disbanded after only a few months when Mosby's Raiders killed half their personnel in a raid. The Loudoun Raiders spent years trying to catch Mosby's Raiders, but were unsuccessful and absorbed into the conventional army.
The Jessie Scouts, however, are considered by the U.S. Army as their first Special Operations Force (SOF). Only 58 men total, they did actually use Confederate disguises. Operating in the sideshow of Missouri, they largely survived the war, and went on to do grey op missions in Mexico that even today never really made public record.
On a fun tangent, the commander of the Jessie Scouts, Charles C. Carpenter, was a fantastically colorful character: a pre-war Jayhawker who after the war would dress like a 1950's depiction of Davy Crockett and lead an attempt to illegal settle then Indian lands of Oklahoma. After multiple attempts to stop them, President Rutherford Hayes ultimately had to send the Army to destroy the "Boomerr" colony.
There were also various other special operations conducted by the Union side. James J. Andrews "Great Locomotive Chase" is particularly well known for being the origin of the Medal of Honor and being almost comedically inept. Andrews, a civilian spy, pitched quite the CONOP in 1862. Smuggle a platoon sized element to Atlanta as civilians, steal a train, and then drive the train all the way to Chattanooga while destroying the railway as they went. Being early in the war, nobody doubted something this ridiculous and he was greenlighted the same day. He recruited 23 U.S. Army volunteers for the raid and they agreed to meet at a guest house in Atlanta.
Enroute, two of the men were conscripted into Confederate ranks. The day of the mission, another two overslept and missed it. While they succeeded in stealing the train, it was immediately noticed as it was broad daylight and that stealing a noisy steam locomotive from its conductor at a station isn't exactly a stealthy move. The main objective of the mission, actually destroying the railway, was impeded due to rain and a complete lack of demolition tools. They obviously didn't know how to gauge fuel consumption and ran out of fuel 20 miles before Chattanooga. They attempt to evade into the woods but were all captured and/or executed. Even had they made it to Chattanooga, the Union offensive had met reality since their briefing almost a month prior and Chattanooga would have still been in Confederate hands upon their arrival. The whole thing was a a suicide mission whether they knew it or not. As such, the 19 military members who actually perfomed the mission were the first Medal of Honor recipients. As a civilian spy, Andrews could not receive the award.
For the sake of not making Union special operations look completely terrible, a LT William B. Cushing, U.S. Navy, is very underappreciated in history. His lengthy obit in the NY Times is entirely dedicated to how much of a badass he was during the Civil War. He spent the first half of the war conducting amphibious raids along the Confederate coast, and his crowning achievement was his adaptation of the H. L. Hunley's tactics to sink the ironclad CSS Albermarle:
http://en.wikipedia.org/wiki/CSS_Albemarle
Sadly he died at the age of 32 of natural causes and hence only made the rank of Commander. Had he lived longer, he probably would have been as well remembered as John Paul Jones.