Can anyone tell me what sights http://www.cheaperthandirt.com/SCP818-7.html these sights are meant to be used with? Are they meant to be replacements for A2 style front and rear sights?
Yes, they replace the A2 style front and rear sights. However, the dots are tiny and are not very visible in adverse conditions. Plus, the front dot is positioned well below the the top of the front sight post blade meaning that you will need to adjust your rear elevation from night to day in order to get the best post alignment. Been there, done that…I’d keep your standard iron sights.
Without a doubt, the only really viable “night sights” is a good red dot sight. Aimpoint, Trijicon, and Eotech are some good names to start. Aimpoint has the best battery life, and Eotech has the worst. Trijicon makes a tritium display if you don’t want batteries.
For $90 dollars I would be willing to try some high visibility enamel from a hobby shop. If you decide you don’t like it later, scratch it off and buy a red dot 
Besides… do you really need anything on the rear site?
While I can’t see any hurt coming from replacing the front sight post with a Triji or simular unit, I can’t say the same for the rear. Think about it, when installed on a pistol, you hold the gun at arms length, line up the sights and shoot. With these, the dots would be right up next to your eyes and run the risk of interferring with your sight picture. Several places sell only the front post for these exact reasons. If you are really wanting to try these, opt for the front only. Besides, it’s quite a bit cheaper to boot.
Gotcha, I think I will just try the front sight. On another note, does it matter if I use a front and rear sight made by different manufacturers? Or is that not important as long as the rifle is zeroed properly and the sights are the same height?
OP, do you have a light/mount for your carbine yet? If not I’d get cheaper sights and get a quality light setup.
You rifle’s light should wash out any benefit from a luminous front sight post anyway. Click on your light and aim it at a safe object. You should see the front sight with no problem at all.
I’ve personally run the setup. Take it from a guy who knows, it isn’t worth it.
No. All you get is the front post and the rear apature (sp). It should make zero differance. I’m really considering the front for a night sight. Yeah, a light will wash it out but I could still make a reasonably accurate shot in low light with the NS alone. It’s not the Holy Grail, but just another tool availiable to use if needed. Won’t hurt, might help, all good.
Troy makes some VERY NICE Tritium Battlesights.
http://troyind.com/battlesights/tritium-battlesights
These are their NEW MICRO BattleSights
info and photos taken from troy’s site
I have just the front post on my rifle.