I’ve applied some thought to this, actually. Not necessarily this thing in particular but liner locks in general.

It turns out liner locks are really a bitch to do with FDM printing for a couple of reasons. I’m pretty much decided they’re a no-go altogether, in fact.

Problem one is that it’s basically impossible to orient a liner lock mechanism for printing. The inherent shape is the definition of the kiss of death for filament printing: You need a long gently curved section that’s separated from the main body by an equally long slot. To avoid layer separation issues, you really want to orient this such that the slot is parallel to your layer lines, but that requires printing either the lock or the liner body with a significant portion of itself hanging in midair and unsupported on one end. This is impossible unless you use a ton of supports, which results in an ugly final product. The other option is to print the liner flat on the bed with the lock bar rising upwards, which results in a really shallow overhanging angle which is likewise impossible to print without supports.

But the main nail in the coffin is that PLA, the most common material, is famous for “cold creeping,” i.e. exhibiting permanent deflection if it’s bent and remains under load, even at room temperature. A liner lock mechanism is under load all the time whenever the blade is closed, with the lock bar straining against the heel of the blade all the time. This is a textbook example of a cold creep pitfall. Even if you managed to print such a thing the lock bar would turn into a wet noodle and after leaving it stored for probably even only a few hours it’d take a permanent set and wouldn’t lock anymore.

Acrylic (plexiglass) takes a lot more of a bend and/or exposure to way higher temperatures before that becomes an issue. You can mitigate it somewhat by printing in something other than PLA, but the more complex your part is the more of a pain in the ass that becomes. I believe ABS/ASA exhibit the lowest amount of permanent deflection under load out of the commonly available printable materials, which is why I make my Rockhopper liners out of it. But even it takes a noticeable set after a few days which is a surprisingly short amount of time. With how little I bend the spring bar in a Rockhopper it doesn’t take enough of a set to cause the spring action to quit working, but the difference is still noticeable.

A printed liner locker might work in ABS but given all of the above I haven’t been arsed to try.