There shouldn't be a 44 mm top end on any version of that model, but of course someone may have replaced the original with one. Measure the bore of that cylinder.
During the first years of the EPA version they used a closed port 45 mm top end though, instead of the more common 46 mm open port one. The serial number will help telling what your saw originally come with
The 45 mm closed port one is preferable to the 46 mm open port one, and more so if the 46 mm one is an aftermarket one and the 45 mm an OEM one.