Hi, guys,
I don't know where those serial numbers are coming from, but the cut-off numbers are 800,000 for Springfield Armory, and 285,507 for Rock Island.
So, Dog1, unless you have a Rock Island rifle, you have a so-called "low number". Many have been fired extensively over the years with no problem, but some were brittle and could fail. The problem is that there is no way to tell, short of destructive testing, which is which. I recommend not firing it.
Jim