I think the footprints they documented were 'pillar' type prints that were compressed at the time they were made and later wind swept away the surrounding loose snow. For the most part, it should have been easy to identify old vs new tracks.
Yes, you are absolutely correct.
Also, the very formation of these "pillar" type footprints gives significant information about the wind conditions at the time when these footprints were made. This is very important to note, because it has been proposed that sound phenomena caused by strong winds scared the Dyatlov group of from the tent. However, it cannot be so because there was no such strong wind in the area on the night of February 1, 1959.
To illustrate that point, I will quote from Svetlana Oss' "Don't go there":
"Modern experts say that the formation of specific footprints (raised columns) observed on the slope could only have been possible if the wind had not exceeded 3-4 m/s (6.84 mph). There were several experiments done on the slope in 2013, performed under different wind and temperature conditions. They were sponsored by the Russian newspaper Komsomolskaya Pravda. The footprints mentioned could have formed under different temperature conditions, but only if there had been a snowfall that put at least 7 inches of fresh snow upon an older, firmer layer of snow underneath. It took approximately 15-17 hours for those raised footprints to form. Folks were walking and running in their socks and there were also rescue team members who walked around in their boots. Both left these raised footprints. But in less than a day they were obscured by the wind, which was 15-18 m/s (33-40 mph). There are many factors involved in their preservation, such as the sun, the wind and the temperature. As Brutsnitsyn earlier testified for the criminal case, some of these footprints can stay visible for the whole winter."
"The fact that the Dyatlov team's raised footprints were well preserved after almost a month suggests that the winds permitted sufficient time for them to get firm due to insulation and subsequent freezing. So the wind couldn't have been more than 3-4 m/s, which only confirms the weather report Lev Ivanov used. So we can be confident that from 17:00 to 24:00 local time on February 1 the winds were within 3-5 m/s. Thus there was no tornado-like vortex, and the shape of the landscape itself was not enough to create this odd sound effect."
(Quotations are from Svetlana Oss: "Don't go there," pages 113-114)
That is why these footprints are so important.