Keep in mind original StarVR was LCD at 60hz. The quad rendering I believe was introduced in StarVR One.
Index release Apr 2019
5k+ 120hz & 144hz mode came after(announced in Jan 2020)
5k+ initially released in 2018. With the first model when the new 120hz/144hz modes unavailable with a max top refresh of 110hz. The first release like the Index had the black dot pattern issue; the Index black dot pattern was not as strong and Valve unlike pimax did not exchange headsets over it - Stating this was normal. Iirc 5k+ serial 202.