You can try and lift the dents out from the bottom with the floor plate removed.
Leveraging the metal upwards using a suitable flat tool against other interior areas of the frame.
But, be aware that the frame was case hardened to begin with. The metal may crack in moving it back into place,,may be micro cracked already,,just the nature of the surface hardened stuff.
I'd suggest lightly annealing the dent with the tiny torch tip like an 0 or even 00. Just turn it blue to kill the hardness.
Case colors or lack of them can be easily touched up afterwards.
It's difficult to get it back the metal into place smoothly doing it this way if it's more than an edge dimple.
A better way is to replace the floor plate w/the screws tightened down.
Then place the frame bottom side down on a smooth steel surface w/a piece of thin cardboard between them to protect it,,a business card works well.
Now from the top of the frame through the bbl lug cut out you can access the dent and tap it down. You'll be doing so at a slight angle, so make up a punch to account for that. Brass works well. The hard smooth surface beneath it allows you to tap the frame dent out and nicely even with the undamaged floorplate.
All that said,,the dent usually doesn't bother anything but the looks.
