OEM Type Bolt Kit for Slant Six

I’m trying to put together a kit using Doug Dutra’s helpful “Bolt Size and Tightening Information - 170, 198 & 225 Slant Six Engine,” published 1-29-20 and available on the .org site.

The McMaster-Carr catalog shows bolts available with and without a non-removable washer, like some of the OEM bolts.

Short of removing all the bolts from an unmolested engine, is there another way to tell which bolts come with a washer and which do not?

Should I source the bolts from McMaster-Carr, or look elsewhere?

The only kit I can find online contains only stainless-steel bolts. I'd prefer something as close to OEM as possible.

TIA

–Walt Jackson