In general would I buy a het without papers? Yes if it was from a reputable breeder, not all breeders provide paperwork.
However in your case I would pass, why? I highlighted the important things.
1# It's craigslist not the place I would for for hets.
2# 1300 grams proven breeder het pied female for $175 this should be your red flag right there, not a chance anyone would sell a proven breeder het pied for $175.