A check of the official geographic names index (GNIS) of the USGS reveals that the name of this feature is "Magazine Mountain", not "Mount Magazine". Although not a hard and fast rule, generally "Mount Xxxxx" is used for a peak, and "Xxxx Mountain" is more frequently used for ridges, which better describes this feature. Magazine Mountian appears in the GNIS as a ridge, and Signal Hill as a summit. There is no "Mount Magazine"
Pretty much most references in the local area (of Arkansas) call this area Mount Magazine. Signal Hill is the official summit. I don't see any reason to change based on the USGS official names, when the whole area is called Mount Magazine State Park.