Brooke Hogan is now offering to pay for an autopsy for Hulk ... saying Thursday she believes there's still "speculation and uncertainty" surrounding her dad's death.
The wrestling legend's daughter extended the proposal on her Instagram page ... just a day after Hulk's wife, Sky, revealed they haven't yet cremated the icon "as our family is making sure every question about his medical care is answered first."
Brooke said she'd personally cut the check for any invoice a medical examiner required .