Baltimore/Indianapolis Colts
1950 Bowman card (Bob Nowaskey). The original Colts wore green and white. These Colts were originally in the AAFC and played in the NFL for 1 year only (1950) before folding. The second coming of the Colts came in 1953 when Baltimore inherited the Dallas Texans (after that franchise failed after playing one season in 1952). The Texans wore blue and white - the reason the Colts have those colors today. 
1954 Bowman Cards
Mid 50's navy helmet "shoes on the back" version
Alan Ameche in a 1956 Viceroy ad
This is a shot of George Shaw in a 1955 game vs the Bears. Many thanks to Ron Verrecchio for this pic and helping to finally date this helmet. Ron says the Colts won 23-17.
1955 Bowman Card
Johnny U wearing the white helmet  "shoes on the back" version.  From 1956
1956 Topps card.
1957 Topps card.
1958 Topps card.
From the cover of a December 1958 issue of Sport. A blue mask (like today) no side shoes version!!!
Mid 50's "shoes on the back" version
1954-55 reproduction by Helmet Hut
1956 reproduction by Helmet Hut
2 very nice authentic reproductions by Helmethut. To the left: Tom Matte's unique 1962 Macgregor helmet. To the right: Raymond Berry's 1963 helmet.