If you send an email to Thompson Center they can tell you exactly when it was made, possibly down to the day.
FYI - That is not a G2 (G2s had no images on the frame, see pic of mine below). Of the pre-G2s, there were easy open, and non-easy open versions. Once you engage the barrel release, does the barrel pop open (easy), or do you need to force it open by hand (non-easy)?
Octagonal barrels (and any with soldered on front sights) are older production.
Assuming the frame is in good shape, it should be worth around $200-250ish if it is easy open. Some shooters prefer the older frames due to the trigger design, claiming they feel better than the G2s.
Barrels are hit and miss. Good ones bring $125-200 each depending on caliber, assuming they are in good shape. I paid $210 for my .41 Mag, and $190 for my 7mm TCU, both 10" tubes in excellent shape.
There are a lot of 45/410s floating out there. They are of limited accuracy because to make the chambers accommodate the .410 shells, you end up with a long chamber that is too loose for the 45 Colt.
If you wanted to sell it, I would do it as a .22LR, and then sell the 45/410 cheap on the side, or just throw it in the deal as it's pretty rough. Or, you could part it all out and sell the barrels and forearms separately (everything can be sold online EXCEPT the frame. Frames are the "firearm" themselves and must be sold in-person, or shipped via an FFL.
I can't give you an accurate value for your unit without seeing it in person. Condition makes a big difference to people interested in the firearms.
Mine: