What is funny, is that this "not in ric" coin is in fact present in RIC. It is RIC 62 for which obverse legend is misdiscribed. The Oxford coin cited has an obverse legend IMP CONSTANTINVS AVG like the coin you show.
P. Bastien note 3 p.258 : "numbers 55, 56, 57 and 59 of RIC VII do not exist in Vienne, neither #62 in Oxford. These 5 folles bear IMP CONSTANTINVS AVG legend and not CONSTANTINVS AVG."