I am somewhat confused.
The one on the right in your picture of the two mounts. See the link below. I purchased these mounts from NAPA Auto Parts (for $24.95) part # 602-1127 and stamped "ACM Made in USA". They have a non USA made mount under this same number(I bought them first -they are like my 327 engine mounts -I returned them and bought ones like the link below).
I was sure I remember having NOS GM mounts just like this link for my first 409 motor in the 90's, I remembered how they looked. NAPA lists the number above for 409 motors.
http://www.ebay.com/itm/61-62-63-64...Parts_Accessories&hash=item53ed2d223e&vxp=mtr
I just tested the these new mounts on my 409 motor for my convertible and they bolt up like they should.
Paul