Technically they're sort of neither as they have a number of differences from each. However, they're closest to a Colt Government or non-collet-bushing (aka modern) Series 70, as they lack the Series 80 firing pin block. They do have an additional safety mechanism (ILS) in the mainspring housing (a new MSH removes this, but unlike a Series 80 firing pin block, this has no real interaction with the characteristics of the trigger pull) and they also have some dimensional differences with regard to their firing pins versus Colt's firing pin size.
Short version is they're what we now call a Series 70, without a colleted bushing (which Colt got rid of shortly after introducing it, hence why Springfield does not incorporate it).