Hi Nero,
I got my G. pulchripes as a 1cm sling and have raised it to it's current size at about 6-8cm.
This does look very much like mine did when the markings first began to appear at around 4-5cm large (mine has molted twice since then and the markings are very clear now).
You should know for certain with the next molt as the golden splashes on the knees and legs will be easily identifiable then. I can faintly see the markings on the knees in your first picture, mine also appeared as a grey/brown before the molt where they turned gold. The urticating hairs also look of similar colour to my specimen's at that size. The problem is that most T's look alike as slings.
Unfortunately, unless you're willing to extract hemolymph from the T and have expensive DNA testing done, the best will be just to wait until the next molt and see if you have a G. pulchripes or a nice new surprise