[Tiara Open] Cockpit bolster removal

[Rick B]

I have a 2005 36' Open and the cockpit bolsters are in need of re-upholstery.  The boat has a tuna door and built in bait tank.  How do you remove the tuna door bolster and aft bait tank bolster?  Is it just the "Z" bracket holding it on?  I tried using a rubber mallet on the tuna door bolster and it didn't budge.  Im kinda afraid of hitting it harder unless I know that's all that's holding it.  There is absolutely no access for it to have a bolt holding it.  I haven't even tried removing the bait tank bolster yet but there is no access to that either.  The port and starboard bolsters do have a couple of bolts.  Anyways any suggestions or pictures would help.  thanks 
Rick