The first example,
a natural metal/ white underside (common in the 1950s and 60s)
B-52C, comes from the 20th Bomb Squadron (Heavy), which operated from
Algeria, Tunisia, and Italy during the Second World War with B-25s. The
unit later operated B-29s, B-50s, and other aircraft before deploying its
Carswell AFB, Texas based-B-52s of the 7th Bomb Wing to Southeast Asia
from September 1969 to March 1970. Now known as the 20th Bomb Squadron
in the Eighth Air Force, the unit flies the last model Stratofortresses
from Barksdale AFB, LA.
The 96th Strategic
Aerospace Wing is featured on the next aircraft, a D-model. The Wing
served proudly from England during WWII, taking part in dozens of bombing
missions, including support before and during D-Day, before later flying
humanitarian missions into the Low Countries. While no squadron is
listed, the sheet's example should be from the 337th BS, operating from
Dyess AFB, Texas, which began using B-52s in 1963. The Wing later became
the first operator of the B-1B Lancer. "Big Country Bomber" has the same
paint scheme as the other two bombers, in that it has a black underside
with camoflage on the upper surfaces.
Before beginning B-52 operations, the 92nd Bomb Wing (Very Heavy) flew B-29 and B-36 bombers. The first B-52 the unit received arrived in 1957. From March- September 1968 and the same time in 1969, B-52Ds and KC-135s from the unit took part in operations in Southeast Asia. They continued in June 1972 until October of 1973. They later operated B-52G and H models at Fairchild AFB, Washington, until the unit deactivated.
The 306th BMW flew B-17s in World War II, followed soon after by B-29s and B-47s at MacDill AFB, Florida. While at MacDill, the wing, which was the first to receive the B-47, took part in filming some of the movie "Strategic Air Command." Later, the wing began transitioning to the D-model BUFF at McCoy AFB, Florida, just outside Orlando in April 1963. The example aircraft was a D-model, which had the Big Belly modifications that the unit began in December 1965. The Wing deployed to Southeast Asia in support of Operations Arc Light and Young Tiger in September 1966, basing in Guam and Okinawa, as well as U Tapao. The Wing deactivated in 1973, but did resurface from 1976-1992 in Germany, until a permanent Air Refueling Wing established in England to head tanker operations in Europe.
This sheet is usually pretty hard to find, and as a result, Ebay prices can get steep. However, if you must have something different than what Revell/Monogram offers for options, this is an essential sheet.
Sources:
http://www.maxwell.af.mil/au/afhra/wwwroot/rso/rso_index.html (fantastic site for most USAF organizations)
http://www.306thbw.org/ (specific to the 306th BW)