for that matter?

[KuaiLe]

Dear Teachers,

I read this from p.219 in Mirror Mirror by Gregory Maguire:

"The comb was a lovely Spanish piece that had belonged to some courtesan of her father's -- perhaps her own mother, for that matter. The rack of pins curved inward for better purchase."

What does it mean by "for that matter?"
What is "the rack of pins?"

[Tdol]

1 It's a way of accepting that the first statement could be wrong, though the ownership isn't that important.
2 The pins are the teeth of the comb.