Hi Artesia, the Trijicon RMR sight would require an adapter plate for proper installation since the Glock 43X MOS is designed for the Shield RMSc footprint.
Adapter plate here >>> trijicon.com/products/details/ac32126
Stay safe & have a great day!

Yes with adapter plate.

Try here: budsgunshop.com/product_info.php/products_id/714029798/ch+precision+weapons+chp+adapter+plate+for+glock+43x48+mos+converting+it+to+a+trijicon+rmrsro+holosun+507c407c+508t

Artesia, Yes it can be installed: with this mounting plate and a couple of minutes of work, you will be more than satisfied!!!

Yes it can 100%, with the addition of the adapter plate below.
budsgunshop.com/product_info.php/products_id/714029798/ch+precision+weapons+chp+adapter+plate+for+glock+43x48+mos+converting+it+to+a+trijicon+rmrsro+holosun+507c407c+508t

Hi Artesia and welcome. Yes you can with the following required optics plate: -- budsgunshop.com/product_info.php/products_id/714029798/ch+precision+weapons+chp+adapter+plate+for+glock+43x48+mos+converting+it+to+a+trijicon+rmrsro+holosun+507c407c+508t ---------------- Be sure and use a dab of blue loc-tite to secure the screws so they don't loosen when firing. Give it 24 hours before sight in / firing. Cheers, stay safe and enjoy!

Good morning to you!! You can install a Trijicon RMR on a Glock 43x but to do so you would need the correct mounting plate. See below link for more information. Hope this helps. Have a good rest of your day.
🇺🇸🇺🇸 'Merica' 🇺🇸🇺🇸
budsgunshop.com/product_info.php/products_id/714029798/ch+precision+weapons+chp+adapter+plate+for+glock+43x48+mos+converting+it+to+a+trijicon+rmrsro+holosun+507c407c+508t

Cool name Artesia!!
Yes, a Trijicon RMR can be installed on a Glock 43X, but you'll need a compatible mounting plate or adapter. The Glock 43X is a slim, micro-compact pistol, so you’ll want to ensure you select an RMR-compatible plate that fits the slide cutout of your Glock 43X.
Hopefully the above info helps and hopefully you'll catch some good Labor Day sales Artesia👍🏻
Please take care and stay safe.