I would estimate the 12 bore sidelock at 1000-1500. Sorry for the broad ranges, one would need a number of additional pictures to narrow it down. The brand again doesn't help any, and lower grade sidelocks don't seem to be going for much right now.
If you are wanting to sell them, I would suggest posting them on Gunbroker where people can bid on them. Start them on the low end, and perhaps on a 10 day auction. That's a good way to sell them for about what the market is at. Or you could put them up for a fixed amount for a month before going to auction- but if the figure is lower than what the market is, you might not get as much. I would also suggest a dozen or more pictures per gun, including the proof Mark's on the barrel flats and action water table. Hope this helps!