Thanks to the meticulous research of Nathan Bellew, we can now confirm the original shirt was an olive green Sears brand work-leisure shirt. We don't know exactly what fabric treatment (Penn Prest/Perma Prest/etc.) but we are sure now that it was Sears, rather than Big Mac.
As many collectors and cosplayers know, Big Mac and Sears manufactured nearly identical work shirts from the 1950's to the present. They changed slightly with each passing decade, but in the 1970's and early 1980's both companies made their work-leisure shirts with giant disco collars. Like so:
The two brands were nearly identical in almost every way. As Nathan discovered, the key to discerning the brand used in the film lies in the pocket stitching.
Apparently, nearly all Big Mac brand work shirts have square stitching in the pocket corners, with a cross stitch that's a bit less than an inch from the top of the pocket, passing straight through the button. Like so:
But Sears workshirts of the period have a triangle stitch in the corners... and a horizontal stitch that sits a bit lower. Like so:
The hero shirt bears these two vital characteristics. The triangle stitch:
And the lower horizontal pocket stitch (below is Big Mac on left, Sears on right; bottom is the screen-used shirt):
So there you have it. Have some of these shirts at home? Take a look at them and see if that bears out. I have several of them and this distinction is borne out on every one.
As many collectors and cosplayers know, Big Mac and Sears manufactured nearly identical work shirts from the 1950's to the present. They changed slightly with each passing decade, but in the 1970's and early 1980's both companies made their work-leisure shirts with giant disco collars. Like so:
The two brands were nearly identical in almost every way. As Nathan discovered, the key to discerning the brand used in the film lies in the pocket stitching.
Apparently, nearly all Big Mac brand work shirts have square stitching in the pocket corners, with a cross stitch that's a bit less than an inch from the top of the pocket, passing straight through the button. Like so:
