sounds totally similar to my experience.
a couple years after my MI symptoms (turned out to be BP1) started showing, all the docs, etc started saying BPD traits were there too.
then I find out that almost 2 years ago I had been diagnosed with BPD as well upon an inpatient discharge, and my psychiatrist I had this past year agrees.
however, my therapist, just a few days ago, told me that she does NOT believe I have borderline. she says that therapists have this kind of knowledge with each other that they can just tell if a client has BPD from the way they act in session, and I'm not that way at ALL.
seems to be BP and BPD overlap sometimes, especially with women & young adult women like myself. annoying, i dislike the idea of bpd and i disagree with a lot of the traits cause i have good relationships and I'm not incredibly impulsive.
I think it truly matters only for insurance coding and treatment options. meds have worked, as has DBT, but DBT began prior to BPD traits on my charts.
it's frustrating, but I agree with above poster, work on the biggest issues first, then do some searching and researching to see what makes sense.

EDIT: I'll add that i think DBT can work for ANYBODY. you don't have to have had mental health issues for it to be helpful. BPD's not a requirement.