Yeah I’ve looked at that A LOT, myself, I think it’s the button under the fabric kinda showing through as the fabric has worn around it. Here’s another pic of mine, kinda looks like what you are talking about. Right side fabric worn where the button snap is…
That makes a lot of sense. What a great pair of coveralls you have there, dude!
Thank you very much, if only they fit. Lol
What a shame…
Too big or too small??
Too small.
Lame! Those are the closest pair I’ve ever seen as well.
Make a life-sized with them! 
I was watching the 35th Anniversary Blu-ray the other day and saw (via the ol’ pause ‘n’ scan) no hammer loop when The Shape gets in the station wagon to follow Tommy at the school and also no hammer loop when he gets out of the car at night to watch Annie enter the Wallace house. The image Kaizu posted from H1 clearly shows one, though.
Also, the coveralls The Shape is wearing in the scene where he’s trailing Tommy have very frayed sleeve cuffs (particularly the right cuff). This is clearly seen in the over-the-shoulder shot from the back seat. This seems to contradict other shots (i.e. the Dr. Pepper photo and when The Shape grabs Richie by the shoulders) in which the cuffs seem less weathered.
Maybe we can’t find a 100% accurate pair because two (or more) “close enough” pairs were used in filming.