NOT IN RIC
UNLISTED ISSUE. RIC lists T|F/PTR emission which was was continued after the 1/96 reduction [RIC VII TRIER 39-60]. But there also should be added similar lighter emission of unmarked folles with busts of Mars and Sol on reverse [RIC VI TREVERI 877-895]. The main problem is to distinguish this later part from the earlier one, issued on the 1/72 standard. As Sutherland wrote in RIC VI (footnote 1 on p. 227): "It is not always easy to distinguish this earlier and heavier unmarked series from the lighter one, with the same types, which appeared after Maximinus' death: the weight-peaks are quite distinct from each other, but the light 'heavies' and the heavy 'lights' inevitably tend to overlap".
Probably the most crucial data is not the weight, but the diameter of the die, i.e. the diameter of the beaded circle (which should be not confused with the diameter of the flan!). For earlier and heavier coins, issued on the 1/72 standard, we may assume that the diameter of beaded circle is at least 21 mm. For lighter coins, issued on the new 1/96 standard, this diameter is significantly smaller - c. 19 mm.
Of course, it is sometimes hard to extrapolate the diameter of the die from the diameter of the actual flan, so the attribution is not always certain.
Note that the 1/96 emission was continued up to 316, which is proven by the die match discovered by Genio popvli romani. Compare obverses of coin from 1/96 emission with Sol [2.99 g; 19-20 mm] and of coin from T|F/ATR emission [2.90 g; 19 mm; TRIER 113].
See also: Lawrence H. Cope, "The sequence of issues in the long T/F series of Constantinian folles minted at Trier, A.D. 309-315", Schweizer Münzblätter 1969, no. 75, pp. 59-66.
Coin should be listed after TRIER 60.
TRIER [after 60], CONSTANTINE I, UNLISTED ISSUE [Bust of Mars]; obv. legend 1c, bust B5
TRIER [after 60], CONSTANTINE I, UNLISTED ISSUE [Bust of Mars]; obv. legend 1d, bust B3
TRIER [after 60], CONSTANTINE I, UNLISTED ISSUE [Bust of Mars]; obv. legend 1d, bust B4
TRIER [after 60], CONSTANTINE I, UNLISTED ISSUE [Bust of Mars]; obv. legend 1d, bust B5