Fastener heads

I just received a 7 bolt frame connector set from Beard Machine. It connects 640 front and rear frames & motor plates/transmission. Was there a preferred direction for these bolts? Without input I would think they went in left side with nuts on the right consistent with shackle bolts. My stripped chassis had no engine, transmission or motor mounts, only a big piece of iron bolted to front and rear to keep it from pivoting at upper frame bolt and collapsing.

My manual is a fine copy of a copied copy so it is hard to tell from that.

The 741 manual uses pictures of a 640 in various sections. Nuts look to be on clutch side for the engine plate bolts, but the other way for the bolt under the seat.

Thanks!