I purchased a 2007 ST-1300 from a private seller recently, and it came with a backrest installed, but no top case. However, I noted that many ST-1300's online have a top-case. Q: did the original bike come with a top case, or is it an add-on accessory sold as a non-Honda product? Or as a Honda product? How much do they cost new and used? Thanks. Trophimus.