Open save file(Slot1 and Slot2 file) by hex editor. (HxD is free hex editor)
Then change below value
49 73 44 65 76 65 6C 6F 70 65 64 00 0D 00 00 00 42 6F 6F 6C 50 72 6F 70 65 72 74 79 00 00 00 00 00 00 00 00 00 00
to
49 73 44 65 76 65 6C 6F 70 65 64 00 0D 00 00 00 42 6F 6F 6C 50 72 6F 70 65 72 74 79 00 00 00 00 00 00 00 00 00 01
These values mean 'IsDeveloped / BoolProperty / True or False'
After change the value from 0 to 1, you can by all parts in shop.