Steering box bolts- metric or standard?

[Handlebars]

I just had the SBS kit installed at a body shop. They put new grade 8 bolts on the steering box, I could have sworn that the old ones were metric. Didn't I use an 18 mm wrench on them before? Is there a way of predicting which fasteners are metric and which are standard on my '97?:smsoap:

 

[Loose_Nuts_Enterprises]

Metrics, on hardened bolts will say 8.8, 9.8, etc to indicate grade. I believe that the steering box bolts are standard. Saginaw is an old american company so this would further my suspicions of a standard thread. IIRC, they are 7/16 coarse threads.

Dan