Yeah even if it's a reg, I prob still call. A reg rarely has 6x in his range, especially considering he is calling the 3bet OOP. And he might fold 33, and we expect to be 4bet by AA some % of the time. So really the majority of the time the top of a regs range will be AK; however, we obviously also expect to get 4bet with that hand. So a check/shove on the turn from a reg would be a relatively bizarre line, and I don't think he could be repping much. So I'd def pick it off barring reads otherwise (VERY TIGHT, flats 3bet with AA bvb, etc.)