By 'will try it' I hope you don't mean you'll try reacting the sulfate salt in an HI/P reduction.
Geeze is almost correct; in fact, the sulfate reacts a little too well, as the sulfate (SO42-) ion is reduced to hydrogen sulfide (H2S) by HI (as well as by many other reagents, including formic acid). The chloride ion cannot be reduced by HI so - as Geeze said - the hydrochloride salt is the better choice. Causing avoidable side reactions is never wise.
According to an article in the journal C. R. Hebd. Seances Acad. Sci., 152 (1911), 441-441, a 99% yield of H2S is obtained when reacting sulfuric acid with aqueous HI in the presence of phosphorous acid, H3PO3. These are the exact conditions you'll be exposing the salt to in your reaction.