Hair-metal fans need be cautiously optimistic in anticipation of tonight’s Def Leppard show at Bridgestone Arena. Citing “a band member’s bereavement,” the aggressively British, second-wave glam-rockers-gone-Mutt-Lange-tailored-power-balladeers pulled out of their August 2009 appearance at the arena (then The Sommet Center) a mere day before they were set to rock it. Two months later — and two days before a scheduled makeup date — the band cancelled the remainder of its 2009 North American Tour, citing “unforeseen personal matters.” If the 25 years of ass-filled stadium seats that have elapsed since the band’s colossal (and rather extraordinary) hits cavalcade Hysteria is any indication, the Nashville faithful won’t let those cancellations keep them from showing up with horns raised. So let The Lep ring in Fourth of July a day early with a little pyromania of their own. As was the case with the band’s phantom 2009 show, fellow Reagan-era, pop-metal stadium-gladiators Poison are slated to open the show with a fine-aged, all-killer-no-filler fireworks display of fun-loving hits and bandana-banded hairpieces. Giving Bridgestone-bound heshers young and old an undisputable reason to arrive early, Lita Ford rounds out the runaway arena-rock extravaganza. Lookin’ for nothin’ but a good time? Look no further.