Yes actually, using model:GetExtentsSize()

local modelSize = model:GetExtentsSize()
local primePos = model.PrimaryPart.Position

rightTopFront,leftBottomBack = primePos+Vector3.new(modelSize.X/2,modelSize.Y/2,modelSize.Z/2),primePos-Vector3.new(modelSize.X/2,modelSize.Y/2,modelSize.Z/2)

local region = Region3.new(righttopFront,leftBottomBack)
-- now you have your region