Yes and no.  Since you can't do data conversion of 2020 returns, you'd do the conversion with a 2019 return.  This means you'd convert the 1120 to 1120S with 2019 (instead of 2020) Lacerte, then export the data files of that 1120S return for data conversion in PTO.  This should get the assets and depreciation details into PTO but you'll probably need to make adjustments for everything else since it was not really a 1120S that your client filed for 2019.