Never seen this stem variety before. I have a "Hurlingham" but the stem is the standout here.
http://www.ebay.com/itm/Sasieni-Four-Dot-Hurlingham-Made-In-England-vintage-/252411547600?hash=item3ac4e68fd0:g:B8QAAOSwnFZXUHKs
My first impression is that it is a replacement, going by the heavily buffed area at the stem/shank junction, also the dots look too close to the same.
AGreed, total mismatch between the pieces here, that's not a real old Sasieni given the stamping, not old enough to have an amber stem! Just looks like a real poor replacement to me.
Looks to be a replacement stem, and if you're going to the bother of replacing the dots, why not blue, like they're supposed to be? I've seen lots of different shades of blue dots over the years, but those don't have any blue to them that I can see.