Hi,
yes i was thinking the same , and i found a function that can calculate the faces area , so i can compare them to be more accurate , the functions name is UF_SF_face_ask_area , but i have difficulties to crate it .
as an answer to your question, the parts does not to be exactly similar but i think ,if i can calculate the areas of faces i will be able to filter them , because the dimensions of these parts are much smaller then the other parts.
as an exemple, these parts are flanges providing connections between the tubes.