These are valid questions that have been asked. The 026 was made with different types of top covers. Some of the older covers had NO decomp hole, some did have the hole and when the saw was not a "pro" with a decomp cylinder the hole had a rubber plug insert. There are also 2 different kind of filter box covers. One for the later model saws with compensating carbs, and the older style with the round nob that is fitted for the old slim style filter. It may help your cause if you could state the exact ones you need.