I have fitted my Dogbone mount, and re-used the old bolt. Looking at it, and using my engineering experience, I don't believe it to be a stretch bolt.
One thing that does concern me, is the length of the bolt is not enough, given the extra thickness of the DB bush, and the large washer.
Can someone look at ekta for me, and perhaps post up a pic of the bush assembly, and bolt part number. In the spec it may give the bolt length, thread size and pitch. I could do this at home, but it would mean getting under and removing the bolt agian.
I am going to look into getting a proper High tensile steel bolt, the correct length.
Cheers in advance.
Dave