Yes Warrehouse, this was my first thought too. (although officially valid till 31. dec.1876, practically litoghraphy stamps vere used till mid 1873- after that they are rare). This is engraved (my opinion is based especially on the whisker- it is nicely detailed, clear, thin lines). I don`t have a litography

to show, but some scans and more detailed explanations will hopefully follow.
Now some scans:

Here is one distinguishing mark (called D2), it appears on your`s too. Stamp was printed in sheets of 10x10, this mark appears on column II, III, VII, IX (engraved issue). And your`s is from column II or VII, because I now observe another mark (E2- this appears together with D2 in column II and VII every row). I can`t find one with that mark, I`ve tried to draw it on the same stamp: two thin lines, I can see it on your`s:
