Hi David,
The link doesn't work, so it is hard to tell, also more info might help to identify the age, such as thickness, quality of the iron is there folding line, and so on.
IMHO, from what I can see, I don't think it is pre-Edo, it looks like Tosho school, but too small for pre-edo tsuba, also the hitsu-ana indicates to more later tsuba. The design is also too elaborate for early age tsuba and more appropriate to Edo era. This of course may change due to new info on the tsuba and better photos. Mike