Never hurts to ask, nicely...
Unless you were able to get a MR for pretty cheap, I would just stick with Gold and see what they offer you. That is just me, I haven't stayed at the Conrad though, so maybe others who have stayed there can post their experiences.
This would be after I asked in the comments section, "HHonors Gold guest would appreciate any available room upgrade".
As well as presenting my Gold card (unobtrusivly) w/ credit card (to make sure they have my HH # on file).
And it never hurts to ask, if they do not confirm, "Mr. Cisco Kid, we have upgraded you to the Jr. Presidential Suite, we would have given your the Presidential Suite except the Sultan of of Kyregisnki is residing their presently."
Just a simple question, with a slight smile and a slight head bow... "Were you able to get us an upgrade?" The same goes for the breakfast certs.
And I would do the above whether I was Gold or Diamond, if I was not told I recv'd the upgrade and/or breakfast certs.