Good evening,
yes, there had been german troops with short boots even before the outbrake of the war in 1939. The mountain troops (Gebiergsjäger / Gebiergsjaeger) wear them, I found a picture of General Eduard Dietl wearing putties and a fieldcap in Norway 1940.
If your soldiers wear fielcaps (Afrikamütze / Afrikamuetze) and short boots you can declare them as Gebiergsjaeger at Stalingrad.
A second point: From the middle of 1941 the army (Heer) give lace up shoes to their soldiers to save leather, even to front troops.
Yours, Sebastian