I never noticed it on that picture, I just noticed it on the version with less resolution.
You're right, the front bolt head does look thicker.
That seem to be one of those details that most would not want in to replicate on a blaster, similar to the crooked flash hider on the ANH Blaster
I think the motor coil text is pretty clear. Not only are the correct letters there but they are in the correct place in relation to the holes.
http://i678.photobucket.com/albums/vv142/kurtyboy2/props2/motorcoiltext.jpg
"Well, considering we've ID'd the chopped up motor/coil part as those left side greeblies, I think we've got that area covered."
I have my doubts. I don't know why they would chop up a cast piece of plastic just to create what is basically a spacer. Especially considering all the bolts and other hardware they used on the blasters. Obviously they had access to plenty of hardware. Remember, there was only one motor/coil part in the V8 motor kit box. If they used a second piece it was either cast or from a second box. I think the "lettering" we're seeing is basically an optical illusion.
I don't think they exactly did it on purpose. Looks like they attached the full piece above the trigger, didn't like it, pried it off and that's what's left
The words are inboard. If they had attached a full piece the words would have been out board