He could if he looked it up but that takes time and 026`s are now old saws so unless you were talking to an older tech the newer tech has to take time to go back through Media Cat and find all the changes. Even the older guys that worked on 026`s when they were current models would have forgotten all of the changes by now. Looking through Media Cat and pulling over 16 different 026`s off the shelf enabled me to help Jimmy find 4 different choices for vents, there may even be more but the tall black ones were the early ones, after that changes were made in the size and design of the vents and caps. The only way to determine which vent is needed, if the original is no longer installed on the tank ,is by measurement and visual inspection of each individual tank as tanks often get changed out one can not go by engine serial numbers alone.