Well, it depends on what kind of passport you hold.
I'm not sure about the HKID. Mine's just the kind you get when you're here on a working visa. I'm not PR or anything like that. As I mentioned, with this kind of HKID, my Australian passport and $150 HKD, I've successfully applied thrice recently at the border for the Shenzhen-only visa. And each time they only wanted to make sure I had HKID; they didn't seem to care what kind it was, or how many stars were on it.
To be honest, you could spend hours ringing around, or going into the office in Wan Chai to find out, or reading through pages and pages of the past threads, and you'd still get conflicting info.
I'd say your best bet is to just turn up and apply. There's unlikely to be many other applicants the visa office (there were none each time I was there). It sounds like you might have what you need, and the very worst that can happen is you'll have to make the 45-minute train journey back to TST.