Mike:
The easiest way to dintinguish a SO from CO is look above the cross bolts on the bottom of the block. Right above them, but below the screw-in freeze plugs (another sign of a SO, but can be faked) will be 3 screw-in
oil gallery plugs. If you have these, you have a SO.
On the heads, HR and TP have no heat transfer to intake manifold. Every other FE head will have the riser.
In your first picture, the intake ports in the head do not look tall enough to be HRs. C3AE-6090-K is the first iteration of HR head. The second is C4AE-6090-F, which was used up till early '65. Make sure you look at the last digit (K, or F), as that is the change code and further helps identify the part. HR intake ports measure 2.78 x 1.38. MRs measure 2.06 x 1.38, and LRs are 2.34 x 1.34
Supposedly, SOs were already in production by March '65.
After going back and looking at your 2nd pic, I would say it is a SO. Look at the cam bearing bore--you do not have the
oil pressure relief valve, like a CO would. And, look in the lower left, there is your
oil-relief valve (like a SO). Further, the galleries are undrilled, which is what you might find on a service block or '68, with provision for hydraulics. Undrilled would further point to '65 - '67 engine.
As far as the heads, I would ask them to measure the intake ports for you over the phone.
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