Anita yes it does look as though it is written in a similar way. In addition there is another mark further down that page, which is the Harrach feathers mark and a number and it looks as though it was applied in the same way with pale enamel, as mine. To be honest mine is so worn off that I had a hard time working it out at all without a loup and it was only by photographing it that I could read it (hence the base shot looking so dark which it isn't in reality).
I did find another vase id'd as Harrach that is a similarish shape to mine... but it is really only 'similarish' and whilst it is difficult to tell from photographs, my instinct still says mine looks more like the ones id'd as Loetz on that page 87 (see my comments above about the body and neck of the vase).
So I have question...were the photographs in the Truitt's book based on the catalogued Loetz shapes for id? If so that should confirm their id and I wonder if my (and your) vase shape might be in the pattern books?
I don't have Ricke or Truitt's yet, so until then I'm just working in the dark.