I'm the original owner of a '69 Barracuda 340 that I ordered in the fall of '68. Recently I removed the manifolds for the first time and took photos. Factory was 2 thick conical washers at the front and 2 at the rear with no washers in the middle 2 places. So yes, four washers on each side and no washers on the inner two bolt locations.

These photos are left side: front, middle, middle, and rear. Right side is the same as far as conical washers.

And AMK is the best source. AMK has actual size color photos of each item they sell, so you know exactly what they offer. Items that are exact copies of Mopar fasteners are coded with the pentastar logo and show the Mopar part number. Others who sell fastener kits are mostly just re-selling AMK.