If it is a Springfield it should be so marked along with the serial number on the receiver bridge. The lower numbers are considered unsafe to fire due to heat treatment issues. For guns made at Springfield armory a number above something in the 800,000s is necessary. For those from Rock Island Arsenal, above something in the 200,000s. Sorry I don't have the actual SNs here, but a web search would turn them up for you. Does the floor plate look more like one from a 1903A3? I think all of these, being of WWII vintage, are safe to fire.