Hello jaggy, this is relatively easy to 'fix' with the scenario editor. Just start the editor, and follow these steps.
1. Pull down the 'File' menu, and select 'Open...', you will get an explorer window to search for the scenario file you want to edit.
2. Navigate to '\Panzer Corps\DLC\GC43East\Data' and open the file 'Prokhorovka.pzscn'. Personally, I would make a backup of this file (and Prokhorovka.pzloc) first, and rename the original with '_original' added to the name or something similar and use a copy for editing.
3. Pull down the 'Edit' menu and make sure 'Units' is selected.
4. Scroll the map in the editor to the place where the two SE units appear, on the far left side, somewhere in the lower half you will see the SE Tiger and SE Bf109. Note their strength plate borders, which are silver (aux unit) instead of gold (core unit)
5. Important! Press and hold 'Shift' and click on one of the units, a menu named 'Unit Params' should appear. You can let go of the shift key now.  
 
6. In this menu, look for entry nr. six, which is named 'Auxiliary', and is followed by a ticked check-box . Click the box to uncheck it (the square should be empty) and click the 'OK' button at the bottom left of the menu. The window closes, and see if the unit now has a gold border around the strength plate. If it does, repeat steps 5 and 6 for the other unit.
7. Pull down 'File' menu, select 'Save'.
8. Congratulations on your new core units.
Alternatively, you can download and place the attached file in the '\Panzer Corps\DLC\GC43East\Data' folder and unzip it. Please don't just overwrite the file, rename your original 'Prokhorovka.pzscn' file first so you can revert if needed, because I didn't test this.