I suspect that all the plants of this cultivar now in existence trace back to the plants at Europa-Rosarium, Sangerhausen. The colouring of the individual flowers is very variable, but I have no reason to doubt that both pictures uploaded to HMF are correctly named. We tend to describe colours rather loosely, and the roses that are marked as 'golden yellow' are often rather more yellow than golden. The colour of 'Fürst Bismarck' is very similar to that of 'Gloire de Dijon', and just as variable. Incidentally, I believe that 'Fürst Bismarck' is a selfed seedling of 'Gloire de Dijon' (there is a record of it being crossed with 'Comtesse d'Oxford') and not, as some German authorities (e.g. Jäger) maintain, either a sport of 'Gloire de Dijon' or a synonym for 'Belle Lyonnaise'.