I'll take a stab at this; no guarantees of correctness...
I apologize in advance for my ignorance on the subject of HJ, but my research in this area has been minimal; primarily trying to decipher the markings on my own rifle. So, please correct any misinformation I may have here.
My understanding on the number 7/98, if in fact this is an HJ marking, is that the “7” would be the “Gefolgschaft” (Unit?) and the “98” would be the “Bann”. It is also my understanding that the Bann numbers may not have always remained the same over the years, so sometimes the year of the item needed to be known to determine where a particular Bann was located.
If I am not erring terribly here, then this would be from Kinzigtal, in Gebiete (Region? Provence?) Hessen-Nassau, (#13).