1966 slant six 170 timing mark

I have been told that truck slant engines got the balancer bolt, others maybe not so much. I have two truck slants, both have the bolt. The only suggestion I'd add if you decide you want one, it get that bolt and washer in grade 8. I used a grade 5 in one case and even with a thick grade 5 washer, I dished the washer pretty bad cranking it down. The grade 8 washer will take all you can give it and still be laughing.
Thanks for the info. I'd prefer to have one so I'll probably opt to put one in there. I'd this the timing mark I'm looking for? Top lip closest to the motor? Not sure if pic uploaded I keep getting an error message