I might have the ridge thickness off, but that long highlight is definitely on the ridge and it extends past the base. My drawing is based on the actual photo which is clearer than the Chronicles scan, but some stuff is still lost to the darkness. I only reposted it on top of your scan because I don't have permission to post the original.
Here's a second attempt highlighting some faint, but sharp value differences that might be edges. I'm positive about the outline of the antenna head - that much is very clear in the original pic (yours is too large and drawn too far to the right).
http://www.christrevas.com/rpf/purpleredraw.jpg
Carson's 3D model works well and matches up with pics so I don't see why you can't make it work.
Carson - Is the track scaled correctly in our 3D image?
The base should be about 1/2 inch wide.
As to why the sight broke the way it did...
T-track is rigid. It was heated and bent into the Sterling holes. Once cooled is holds very tight and you don't even need glue. I'm not sure if it's rigid/brittle enough to break on impact. It may have been cut or broken accidentally in a more direct way like pliers or vise (might explain the two scalloped shaped cuts in the right outlined above). It's easy to see how the antenna fell off since there is very little surface area to adhere to.
PS - T-track matches up in ANH, ESB and ROTJ. There are good ANH E-11 blaster pics that confirm the dimensions.
