According to "English Silver Coinage" both "on truncation" and "below truncation" occur for both circulation and proof issues of this coin.
Yours is clearly "below truncation" and I can't see it as a proof - the rim is not sharp enough. Even if it were originally, it would be "impaired" now as it has quite a lot of wear, most noticeably on the lions' faces.
Relative scarcities:
Circulation, JEB below trunc is C3, (common)
Proof ditto is S (Seldom)
Circulation JEB on trunc is R3 (Rarer)
Proof ditto is R (Rare)
(I could not find a table clarifying how Rare each of the levels are, but C3 seems to be the most common, C2 and C being less so. There is then N for Normal, S for Seldom and R through to R6 for levels of rarity.)
Yours is clearly "below truncation" and I can't see it as a proof - the rim is not sharp enough. Even if it were originally, it would be "impaired" now as it has quite a lot of wear, most noticeably on the lions' faces.
Relative scarcities:
Circulation, JEB below trunc is C3, (common)
Proof ditto is S (Seldom)
Circulation JEB on trunc is R3 (Rarer)
Proof ditto is R (Rare)
(I could not find a table clarifying how Rare each of the levels are, but C3 seems to be the most common, C2 and C being less so. There is then N for Normal, S for Seldom and R through to R6 for levels of rarity.)






















