Yup, yours is for a flat mount brake. I am not sure if teh flat mount they sent me looked exactly the same or not, that was a year ago. When I pointed out to Lynskey that the photos on the website were for a IS type mount and that I had already bought a 160mm brake that would fit on a post mount or an IS mount (with adapter), then they sent me a post type mount. And the one they sent me did not function correctly, I told them what was wrong with it with a photo, they then sent me a functional post mount.

Did you already buy your disc brake?

At this link they show a flat mount brake unit. But I have no clue if your Lynskey mount is for a 160 mm brake disc or some other diameter.
https://www.jensonusa.com/TRP-Spyre-Flat-Mount-Mechanical-Brake-BlackSilver?pt_source=googleads&pt_medium=cpc&pt_campaign=shopping_us&pt_keyword=&gclid=EAIaIQobChMI 1PHNmJvw3AIVArjACh2kWgzzEAQYASABEgKw2_D_BwE

I see you have the same dropouts I have for a 135mm conventional hub. Both drive side and non-drive side should have the bolts locktited in with the kind of loctite that can be removed later, blue in color. Or a thread locker that is a competitor to Loctite.

When they started putting disc brakes on road bikes, the roadies did not want a big brake unit, they wanted something small and discreet so that it would look small and elegant and light weight. The manufacturers obliged and created the flat mount.

I am leaving town for over two weeks, the last that I will have web access will be mid day on Sunday. So, get your questions in quick.

Some day someone will ask you what the various components weighed. If you have a luggage scale, you could start weighing things and taking notes before you assemble. I was surprised to learn that my frame weighed less than my rear wheel with cassette and tire on it, but that is a touring wheel with robust rim and 36 DB-14 spokes on a steel axle XT hub so it is not the lightest wheel.

My seatpost went in pretty tight, but with grease on the seatpost it slid in easier.