That is a bit rare - either that is a odd, late or oem post or it's had a cradle transplant as all the Answer body shocks i sold in the shop came with the cnced Answer rocker head on them rather than that cast unit.
And I hate to say this but I believe that post was nothing to do with Manitou, it came from the buyout of another company by Answer (bikepro quotes it as the Roll-r-Post body shock seatpost, precursor to the Answer body shock post)
All manitou posts, even after the buyout were ringle heads on an alloy shafts, they were then replace with the answer rocker