Looking at that excellent photo....it's my 99 in the flesh! Does it have a round, drop in bobbin? If it has an oval, sort of, bobbin case, it's not a 99. Mine is in a walnut cabinet, purchased in 1955....and stilll in good use.
It's not a featherweight, but I'd bank on 99. A wonderful, work horse of a little Singer....not to be found every day.