Caution - SAK collector minutia ahead...Syph007's
thread about the new mag glass got me looking at a new Explorer I picked up recently. It must be a very, very new one because it does in fact have the new style mag/phillips. While looking at it, I also noticed that Victorinox seems to have recently changed their 91mm tang stamp. That got me looking at some other knives I have with the newer 2.0mm main blade, and in the end I found four different tang stamps since 2004:
(Dates are estimates based on the knives and when I bought them).
The first stamp is the old style four line stamp that Victorinox has used since 1986, including the crossbow on the back. This stamp is on some of the earliest 2.0mm blades, but disappears pretty quickly. My guess is they used this stamp for less than a year, given the percentage of 2.0mm blades that have it and those that do not.
The second stamp is what I'd always considered the "new" stamp until I discovered the following two types. Like the 04-05 stamp it's a narrow stamp with a good bit of room to the left and right. The back of this stamp is the plain "Officier Suisse" w/o crossbow. The stamp in this picture if from my VSAKCS 2009 club knife, so it lasted at least into late 2008/early 2009.
With the third stamp we see Victorinox switch to a wider, heavier stamp - the letters are thicker, the word "Victorinox" spans almost the entire width of the tang and the word "Swiss Made" is almost as wide - compare this to the previous stamp where "Swiss Made" was a good bit narrower than "Victorinox". The knife in this picture is a SwissBianco Scientist that was we know was made in mid 2009. Knives with this tang stamp are when we start to see the scissors pivot change from steel to brass.
The last stamp is almost identical to the third, except the "V" in Victorinox is now the same height as the rest of the letters in the word, instead of rising above it like in the previous versions. Incidentally, this style of "Victorinox" (with all letters the same height) was the standard from 1957 - 1985, so this is kind of a retro thing. The word "Stainless" is also a good bit wider now as well. The knife in this picture is a 2011 VSAKCS knife, made (as far as I can tell) in late 2011 early 2012. All knives I've seen with this stamp also have scissors with brass pivots. Knives with this stamp are when we see the new mag/phillips layer appear, indicating that it's a new feature of the last couple years.
All evidence is anecdotal and based on observation of 20 or so knives. The variations in the stamp could just be regular manufacturing variations, but I doubt it.