A few years back when I built my first engine I asked the machinist if I should clean up the rods and the crank of the casting flash. He said I could if I wanted to but it wouldn't matter. Since he's been in the business for 30 years and had Buick experience I believed him and it's proven correct. My stock uncleaned rods are resized only and the stock uncleaned crank is approximately .010 under. 9.98 @ 136.
What is important in my opinion is that the machinist installs the girdle and main caps according to Jason's instructions, plus uses a torque plate, in order to do the necessary boring and align honing. My machinist will then disassemble it, install the mains and measures what he needs, in order to have the crank turned to that less .002. On each throw.
The only thing I'd do in your case is talk to the machinist and be assured by him that he will use a torque plate and install the girdle before the machine work. And hopefully he knows Buick V6's are different than Small Blocks. It's not what you do at this pont, it's what he does that matters.
