Well let's not kid around here--all fountain pens are over-valued; primarily by their manufacturers and ultimately by those of us who buy their products.
With established, name-brand pens, that begins with sky-high MSRPs (that are almost always discounted by at least twenty percent at retail). Which is to say, if you paid retail, you're new to the hobby (live and learn). These same manufacturers (let's take Pelikan, for example) constantly release versions of their established pens with slight material variations and call them Limited Editions--and then price those pens even higher. The associated costs to manufacture these pens have long been recouped, and the remaining costs are largely related to sales, marketing, and distribution expenses. In other words, margins are high, costs are low.
Consider the bill of materials for a nice pen like a Parker Duofold. Lets start with the guts; there are none! For all their external drama, the guts of most nice pens consist of a cheap (but functional) plastic converter inserted into a nice section, a plastic feed and a gold nib. That same section has been around for since Moses, they've made a zillion of 'em and all the tooling costs were realized long before you and I were born. Now it could be a pen with a piston-fill mechanism, and I'll allow those are more labor intensive to assemble, but not too much more to make. Of course the gold nibs aren't cheap--unless you buy them in quantity from another manufacture (as most, but not all companies do), who stamps them out by the hundreds every day. In that case, they're cheap too. So what's left; Barrels and Caps? Also cheap to make now (again, on the same tooling they've used for years and years). Toss in some gold plated furniture (negligible cost there as well), and then add some very attractive packaging, some nice printed material, and there you have it: a really nice pen that cost maybe $35 to make, market and sell, which will retail somewhere in the neighborhood of $400-$800.
Now, I happen to like those pens (Parkers and Pelikans, I have a few of each) and one of the things I like about both manufacturers is their history, their contribution to the development of pens--their provenance! Those guys (and many others) made fountain pens what they were in their heyday and what they have become today (admittedly, pretty much a niche item).
This guy, on the other hand (the tree ring fellow), has none of that--no history, no invention, no provenance . He's essentially selling you a "kit pen"--something he's assembled with off-the shelf parts he's purchased from manufacturers of pen parts who cater to that hobby (Google: "kit pens"). He's not likely making his own pen caps or sections, or feeds, and definitely not his nibs--he just shops for them. Now he's got his angle, I'll give him that. I don't doubt he's manufactured the wooden barrels with the incriminating date stamps (wood is a terrible material for pens by the way--very unstable). But here's the cheesy part: he had to make the barrels to fit the parts he bought; in other words, he didn't determine the optimum barrel diameter he thought a pen should have, he just made it fit. The barrels appear as though they've been cored, or plugged (not turned?) from the poor hapless trees somebody "harvested" (btw, where I come from, that means CHOPPED DOWN, just say'n), so as to any craftsmanship involved, I'd have to see his workshop to know what's actually involved in churning them out, but I'm willing to bet "theirs and App for that" (meaning not much handwork).
So, what's left? Assemble them and find someone to sell them to. Does that justify the $170 they'e asking for them? Especially when compared to real pens made by real pen manufactures at similar prices? I'll let you be judge of that--but don't forget to ask for your twenty-percent discount!