Those Congress-style shoes sound like what they called in the Navy "LOX boots". Aircraft Mechs wore the "Boodocker" style shoe which basically looked like a lace-up, round (and steel-) toed brogan. The LOX boots were similar, without laces, but had the elastic on the sides, so you could slip them off in a hurry, in case you spilled liquid O2 on your foot. I think the leather and soles were specially treated so they wouldn't soak up oil or grease, as well.