Save files contain IPL flags that enable and disable map objects in the game.
The order of the IPL flags is determined by the models\gta3.img file being used when the game is saved.
This site cannot detect your IPL version for you.
Saves will work regardless of which version of gta3.img you use, however there may be glitches, such as
road barriers to other cities still appearing after they should have been removed.
You can check which version of gta3.img you are using by checking it's file size or checksum.
If your gta3.img doesn't match either of these, then your gta3.img is likely modded.
Story Barriers: City barriers will be enabled or disabled depending on mission completion.
Disabled Barriers: City barriers will be removed regardless of mission completion.
Find out which version of gta3.img you have or leave unmodified.