I’m a huge fan of Fiske, and the pens in particular! I’m not sure how often they update those, but one thing you can do, depending on how far down the rabbit hole you want to go, is to digitally check out an older copy from the Internet Archive. (I took a look at 2018’s copy, and Macalester had 4.5 then, so you might start from there!)
There’s also this older thread on Fiske pens that might be interesting, and might give you some data to compare against a more recent copy.