Roman Republic, L. Calpurnius Piso Frugi, Denarius, cast imitation, cf. Crawford 340/1

Cast imitation: Roman Republic (20th century cast), L. Calpurnius Piso Frugi.
AR Denarius (3,08 g, 18 mm).
Obv.: laureate head of Apollo right, behind K. I. below the chin..
Rev.: horseman galloping right holding palm. trident above, L PISO FRVGI / C , in two lines below.
cf: Crawford 340/1 ; Sydenham 669a ; Bab. Calpurnia 11 .

The low weight (min. 0.5 g missing), casting bubbles and the porous surface are clear facts.
The edge is rasped and smoothed but also shows remaining hints (a seam and bubbles) for casting.