Cam belt cover plate, help

I have an early 300tdi defender, when it was new it would have the crank drive gear without the flanges, I am sure at some time it will have had a new drive belt but how can I tell if it has had the updated belt drive kit including a modified cover? I have no documentation for the vehicle, the yellow square that should have been painted on the cover if it had been updated is not there. So before I strip it down and buy the parts to do a cam belt change how can I tell which kit I need. can anyone help?

the cover was only changed on a few ,if with sided crank pulley belt still wears on edge then rear timing cover may be misaligned .you only need sided crank pulley and open sided tensioner earlier type other way round ,its better for belt if driving pulley is the one that guides it

Just buy the updated kit, its not exactly expensive dont forget to get a front cover seal and crank o ring as these dont come in the kit