OK, the days that you were an F-1 visa holder do not count towards the substantial presence test, Therefore only the days that you are on the H1B visa count. So if you switched to H1B in Oct, you will not meet the substantial presence test because Oct to the end of the year is less than 183 days in 2017.
If you claim the treaty exemption, there is no need to file a dual-status.
I updated my answer to include this information.
