This Bacon ff Professional dates from early in the 1906-1920 period that Bacon was in Vermont. Lack of serial number was not uncommon among the early instruments. Most parts and whole banjos were outsourced to major manufacturers. This head inlay suggests it was made by Vega. All featured the 1906 patented internal resonator. The company was rather chaotic under musician Fred Bacon until the arrival of David Day.
The neck is perfectly straight and true -- 1 1/4" wide at the nut. The scale is 27 1/4". The head is 10 13/16". Of course, there is a Bacon tone ring, which is different enough from a Dobson to have been patented but otherwise indistinguishable in function and sound.
There is nothing amiss with this instrument, save aging and normal wear of over 100 years. The Grover "pancake" tuners are an after-market upgrade, probably from the 1920's or 30's.
A "Superior" brand bump case in like-new condition is included.
The only visible fret wear is on the first fret, second string. (See photo.) The rest may have been skillfully dressed at some point. They all play just fine.