How minor an issue can be before it totals a vehicle out, depends on the book value of the vehicle, so yeah something worth only $2K, could be totaled out from a fender bender that damaged the bumper and headlight assemblies. Multiple airbags going off will total something worth even more.
Otherwise, trust no one. All you know for sure is it now has a salvage title and "probably" at a minimum they replaced what was mentioned, or didn't, and are selling it AS IS.
Take it like you would any other vehicle with an unknown history, but also look closely for flood damage, that can take a while to fully manifest itself. Another sometimes related, and sometimes not issue that can total one out is a biohazard, for example it was covered in mold inside and they just cleaned it to look nice but mold spores are still in areas you'll never get completely clean.
It helps if you can talk to the prior owner, but if related/affiliated with the seller, again trust no one.