Regarding this set from a Canadian perspective...
Leopard C2s earlier on in their life had a standard canvas mantlet cover without the later added dual access panels seen on the rubberized versions.
In fact, some of the canvas mantlet covers on C2s were still painted in their Bundeswehr NATO camouflage. That adds even more colour variation to a C2 build along with a NATO camouflaged hull.
The canvas mantlet covers were changed out for the later rubberized version with the two access panels as time went on.
The rubberized versions, in addition to the two access panels, have much larger round metal reinforced eyelets as opposed to the original small rectangular reinforced metal eyelets. This can be easily seen in the Legend Productions part but not mentioned in the review.
Here are images in the link below of a Leopard C2 in 2004 with the original mantlet cover. In fact, the same markings provided in the Takom kit.
So, Takom did not miss the modified mantlet in their kit based on the timeline of their C2 markings. Their mantlet is correct.
http://www.primeportal.net/tanks/dan_hay/leopard_c2/index.php?Page=1 I can state with 100% certainty that the original canvas mantlet covers with small rectangular eyelets and no access panels were still in use on some of the Leopard C2 MEXAS tanks that deployed to Afghanistan in the fall of 2006. A C2 MEXAS with either the original canvas mantlet or later rubberized mantlet is correct.
The choice to use or not use either resin mantlet for a regular Leopard C2 or a Leopard C2 MEXAS is your choice. Neither are incorrect. Base your decision off of details on a specific tank.