Is this what I think it is?

[estott]

To me it looks like a standard recorder which someone has tinkered with- the stylus bar may be a replacement or modification.

[Chuck]

If you can't make it out clearly in the photos then
chances are it's messed up somehow.

Recorders turn up at shows for very reasonable prices
and at least there, you can hold it in your hand and use
your pocket microscope and bright light to examine it
right there firsthand, before making an offer.

A 50-power LED-lit pocket microscope can be purchased
brand new for about $10 tops. That is about the best
tool to carry to a show to look at various styli.

On the subject of the 4 minute cylinder recorders:
I personally would not expect too much from them.
That format has such narrow, dainty, delicate, tiny
little grooves that in my humble opinion they will not stand up well to being played back very many times.

That format is a very tricky balance between having
the blank be hard enough to stand a few plays before
wearing out, versus being soft enough to record
reasonably well.

Even at the narrow groove pitch of 160 TPI for
Dictaphone, and 150 TPI for Ediphone, these recordings
wear out quite fast after repeated playings.

This being the case, I can only imagine what will happen
at 200 TPI! With this as the background then, my
own personal opinion of 4 minute cylinder recording
on 4 minute blanks and then playing them back is that
this would be a fun diversion and an interesting set
of experiments to try out.

As long as one keeps in mind the serious limitations
imposed by this format, it might be a fun and interesting
experience, but not one which would have the robust
qualities of the 2 minute format.

Again, it all boils down to unit-pressure and wear.

Chuck