As always, I take your word for it. xD I probably may just let this one collect dust in my boxes for the time being, unless I decide to release it at some point. The RNG via emulator would make a little more sense, actually. Because after attempting to look up a little further on the user whose OT/ID belongs to, it led me to Bitterlemon's old trade shop on Smogon. (Seems this user has been inactive for some time, too.) Said user also seems to have a lot of OT/IDs belonging to him/her, and I would find it strange if said user owns that many 'physical' copies of the game. But for the OT/ID I have, I did find this within his/her trade shop post: "Soul Silver JAP ID: Ghix (30864) 7942ef72" (What does the one in bold mean?)
7942ef72 Is the PID he RNGed his ID number for to make the spread shiny. It's the PID for the hex-flawless Timid spread in HG/SS. I've been on Smogon once or twice and browsed around their trade threads at times, some people use to list the PIDs they RNGed for in gen 4. I never understood why really, it doesn't tell you anything useful, and it always looked suspicious to me, but I'm a bit jaded by past hackers so maybe that's just my paranoia. Any way, knowing the PID doesn't really tell you anything, and the people who can use the PID to double check the spread are fully capably of finding the correct PID on their own.
As for the several ID/OT combos, that was also pretty common in gen 4. You could only RNG for one spread at a time in gen 4, so if you wanted HP Fire Timid and HP Ice Timid, that meant you needed to play the game twice (well, only if you wanted the pokemon shiny). Quite few people had the ability to extract their save files and could inject them back into the cart at will. Other, like myself, were low tech and had to delete the previous save every time we decided to RNG a different spread. Emu abuse would make this process a lot easier though. Did the trade thread mention tht they played on an emulator? Some users also use to make note of that as well.
EDIT: I just noticed that he lists his file as Japanese. Is the OT in the blocky Japanese font, and does the pokemon have a JAP tag? If not, then regardless of Bitterlemon's legitimacy, it would seem someone hacked one of his pokemon. Even if the pokemon has the right OT font and the JAP tag, however, the problem of the ID number still remains, but the font and tag would give a definitive answer.