The temperature on the moon varies from about 90 K at night to about 400 K during the day. However, the Apollo missions were all timed so that the astronauts would be on the surface around dawn, when the temperatures were relatively mild. Their boots were insulated, and their space suits were designed to be highly reflective.
Pluto has temperatures varying from about 33 K to 55 K. What matters to the astronaut inside the suit is the temperature difference between the inside of the suit and the outside. The rate of heat conduction is proportional to that temperature difference.
If you compare lunar nighttime to a balmy summer afternoon on Pluto, the temperature difference is 205 K in the first case versus 240 K in the second case. Those two numbers are really in the same ballpark, so a spacesuit that was designed to handle lunar night temperatures would probably be fine on Pluto. However, the Apollo suits were not designed for lunar nighttime. Therefore I suspect that the astronauts' feet would have very rapidly frozen, and after that they would have quickly died of hypothermia.
It's also interesting to speculate about what effect the astronauts' footsteps would have on Pluto's surface. I'm imagining some spectacular evaporation of nitrogen ice. It might be so violent that you wouldn't even be able to walk.