They were luminous, they just degraded, when they first came in the mid 90's they worked like a charm, most vendors will even advertise the luminous does not work, though I did see another set up from another warsaw pact country that were for sale and they were luminous and fairly new I believe the life span is about 10-12 yearsI found a couple sets of night sights (German, I think) online. Rear set clips to the leaf sight and has a tritium flip-up dot. Front sight clips to the FSB and has a dot that goes on top of the front sight post. Rear sight dot goes under the front sight dot for the sight picture. A fairly inexpensive mod; I bought 3 sets for $18.
Checking in my darkened garage, these sights are not tritium - or if they are, they've degraded so much they aren't visible - but they ARE luminous. I don't know if the FSBs on AKMs and AK-74s are different, but the front night sight assembly doesn't fit well on my 7.62 AK FSB, although it fits fine on my Siaga .223 FSB.
I've tried several different solutions; my favorite is the TWS rail with their peep sight mounted to it, even though you still have to make adjustments at the front sight since their rear is non adjustable. Yeah, it's a scope mount which you said you aren't after, but it's also a damn rugged rear sight setup, and it's way easier to deal with than the Tech Sights once you get it installed and zeroed. And if you do decide the throw an optic on there later, you're good to go.
The Tech Sights are nice, but the dust cover is a pain in the ass to remove and install whenever you need to field strip the rifle. Main benefits are adjustability and increased sight radius, at the cost of the hassle with the cover. I have a set of them on one of my AKs, but I eventually plan to put a TWS rail on that rifle when funds allow.
Probably the easiest thing to do if you just want a peep sight is the basic MOJO, in my opinion. It's a straight replacement for the factory sight, adds adjustability, at the cost of no improvement to the sight radius. Krebs makes a nice sight too, but I'd rather have the adjustable MOJO. I used to have these on each of my AKs, but they've been slowly winding up in my parts box, as I swap them out for higher end setups with optics and/or better sight radius. I just have the one set on my beater AK now, out of the 4 I originally bought.