Earlier I posted my number 81 coin, a Diocletian marked H Epsilon on the reverse. This is the same coin (#82) with H Delta at lower center. It is not in nearly as good a condition, but it does have H Delta.
Fun to have two examples from different officinae! Here's a post-reform radiate from an uncleaned lot. Here's the third officina. Diocletian, AD 284-304. Roman Æ post-reform radiate, 1.74 g, 19.5 mm, 5h. Heraclea, AD 296-298. Obv: IMP C C VAL DIOCLETIANVS P F AVG, radiate, draped and cuirassed bust right, seen from front. Rev: CONCORDIA MILI-TVM, Diocletian standing right in military dress, receiving Victory on globe from Jupiter leaning on scepter; ΗΓ in lower center. Refs: RIC 13 or 21; Cohen 34; RCV 12833.