They are "Bügelspanner" (trigger guard lever cocking) guns. Made from around 1900 to 1950's, for short-range target use usually with darts but some are rifled. The right-hand one is missing its cocking lever. These aren't that scarce, showing up at gun shows, auctions, etc.
Suggest you Google 'Bugelspanner' for lots of info...
Don R.
if it is 80% that's in the ball park
I will tell you, all of us in this hobby need to spend the money and buy a Blue Book, you will find it is the best money you ever spend in this hobby, is it perfect no but it is better then guessing and the amount of information that you glean from it is worth the price
$80.00 isn't a bad price for a 310 if it is in great shape, but I own both and would go for a 317 because it is lots more accurate with a rifled barrel as opposed to the smooth bore 310. The 310 was actually made for lead BB's but I shoot both lead and steel thru mine with no problem. You can actually shoot pellets in it too, but like I said it is not very accurate with BB's or pellets. The 317 with the rifled barrel I have is very accurate.