Here is the schocker for you. That label which has #48 on the lower right corner is pictured in a book I have. Jalovec 'German & Austrian makers' on page 81 and on page 276 of his general encyclopedia of makers. This maker died in 1866.
Is that your Bass? The FF is not there.
On the bass on Ebay, the Label is the same, worn, torn and burnt to look old. It too is the exact same label, #48 but the 8 is torn a bit.
This is why I do not believe all labels in instruments to be true. Dealers copy them from books or steal them from other instruments and then put them in something to increase their value or make them easier to sell. That FF looks like a brand new burned in stamp. Not even 150 years of dirt clogging the letters. Suspicious?