Here's some updates about information I found. Much of this confuses the issue more than necessarily helping clear things up.
There are marks all over the tube, sights, trigger housing, etc. These are basically numbers inside of shapes. From what I understand these are typical of Soviet production items and are inspector/factory marks. The serial number matches not only all of the trigger housing parts (including all the internals), but also the support handgrip that is attached to the rail, the sights(both front and rear), and the front and rear site guards.
I posted pictures of this on BOCN and only got one person to reply. They checked with their friend who is located in Ukraine and he said that my RPG was made by Kovrovsky Mechanical Factory. I'm not sure exactly how he came up with this but supposedly for a short time this particular factory made RPG's without a factory marking on the trigger housing. So that answers the question of why there isn't a factory marking on my trigger housing.
Also from doing online research I discovered that there is usually a tube serial number underneath the heat shields in the back, which is an area I hadn't checked before. From taking off my heat shields I was able to find markings underneath there. I have posted pictures of those markings below. I don't know if the tube markings are supposed to match up with the serial number that is on all of the other parts but it does not.