Id say National
made in USA
Reading that way , top to bottom. Not sure about the reset .
the stick from the neck to the end block shim the end to move the neck up or down to adjust the neck,
Is it a round neck or square neck?
Is there a cone?
If square the strings are high to play with a slide and should not need reset, If round neck it needs adjusted to play.
The neck on a regular acoustic guitar is also glued in place quite solidly, but it needs to come-apart for the neck to be reset. Looks as though as that applies here as well.
The dot markers at the end of the finger board will likely have screws under the inlays
The neck is definitely glued in and will need to be steamed out for sure. I just can't tell if that block running through the middle of the guitar is attached to the neck or not. This particular guitar doesn't have screws attaching the fingerboard extension, it's just good ol glue holding it down.
I think the screws are found only on the metal body ones and not on the wooden ones.
The strap button should screw out and with some wiggling the neck stick or rod (I think you call it a block) should work loose (like a banjo neck and stick). You can remove the 'mushroom' supports under the neck stick, too. Many of these wood bodied Nationals have a traditional dove tail to attach the neck, but this one likely does not, so I'd double-check to see if screws are under the dots in the fb extension.
Can you post a pic of the inside where the neck stick enters the body? These are usually 'banjo' type set ups and easy enough to remove, then re-shim to get the correct angle, tighten up again, and you're done. Never saw one with a dt and the stick. But you never know!
BTW, check neck relief. Many of these I see have rather bowed necks from high string tension from lap slide playing and high tension. And also the saddle on the biscuit, they're often cut down to lower action as it rises over the years, so you'll want to put a nice, tall saddle on again to get good down pressure for optimum tone.
Of course, there could be a heel block and a neck with a dt, plus the stick, just not integrated into the neck itself, and rather just a support in the body, but I've never seen that combo, but there's a first time for everything. Then you have to steam out the neck in the traditional sense.