Greetings,

The NEC requires that you allocate 2.25 in^3 for each 12 awg wire
entering the box. No matter how many grounds enter the box you only
count 1 ground. Your receptacle counts as 2 wires. Add it all
together and I come out with

2.25 hot going to the receptacle
2.25 neutral going to the receptacle
2.25 hot going from the receptacle
2.25 neutral going from the receptacle
2.25 grounds
5.5 receptacle
========================================
15.75 in^3
2.25 cable clamps inside box
========================================
18.00 in ^3

If you do upgrade the boxes 14 in^3 would be a violation of the NEC.
If you don't upgrade the boxes your inspector will likely allow them to
be grandfathered in but they won't have enough room to hold the wires
without cramming. If you do decide to cram try to avoid pigtails and
wire nuts. Make each wire exactly 6" long. In some tight boxes I have
done away with the wire nut for the ground to save room. Allow one
ground wire to loop 3/4ths of the way around the ground screw attached
to the metal box and then continue on. Allow the other ground wire to
wrap around the ground screw of the self-grounding receptacle and
continue on. Next twist the ground wires together tightly for about
1" but do not put a wire nut on. I only bring this up for the
exceptionally tight box.

Hope this helps,
William