Yes, it does have front threads. Among the Hoya filters, I think only the SMC polarisers don't have front threads because of their "super-thin" design. I have a 55mm Hoya SMC UV filter myself, and it cost me about S$25 at AP when I bought it a couple of months ago.
You mean the UV filter? It's the same thickness as most other normal filters. What I meant in my earlier post was that the Hoya SMC polarising filters are designed to be thinner than other polarisers (which are usually about the thickness of two normal filters), which is why they don't have front filter threads. All other Hoya filters (SMC, HMC, or whatever) are of "normal" thickness and have the usual front threads, to my knowledge.