Seems so. I almost live in my lined bib overalls now, and I actually got 34's and put other pants and lined shirts, etc inside when i wear them. Works well, is all just seems to weigh a lot compared to street clothes. i LOVE these.
Yes they are designed to be worn over clothes. I am a 36 waist32 length and I went with 38w32l.
I did go to gander mountain and try some on before I purchased these though. I would defiantly recommend 1 size up in waist.