My question is when did the NYC do away with the stripes above and below the initials/numbers? I'd like to do the car for 1950 +- 5 yrs.

The 1” white stripes (or black for gray cars) on top of and below of the reporting marks started about 1933 and went to about 1959. For about a year into 1960, a single line was applied between the NYC and the numbers. Then the line was removed entirely. 

For a 1950 +/-5 model, lines on top and bottom of the stacked reporting marks. 

Seth Lakin
Michigan City, IN
NYCSHS Modelers Committee Chairman