Kreator,
Without seeing the guns firsthand I would say the top two are German K98s indicative of the flush butt plate and the bottom one is a Yugo K98 (big brother of the Yugo 48 and 48A) indicative of the wrap around butt plate.
If it's close enough to drive that might be a consideration. For about $20 each, you can buy a 'Go' and 'No go" chamber gauges with which to check the gun yourself when you get there.
Essentially what these do is 'measure' the accuracy and wear (or lack of wear) between the the space where the bolt meets the rear of the round and the chamber walls and seat when the cartridge is seated. Too much wear and the gun may be dangerous to shoot.
For example, if you put an 8MM 'Go gauge' in the chamber and the bolt closes that tells you that chamber will accept the 8MM round. However, that doesn't necessarily mean the gun is safe....therefore, if you put a "No go' gauge in it and it still closes it means the chamber is too worn for safe shooting. The bolt should not close when you put a 'No go' in it.
Depending on who you talk to, one GENERAL rule of thumb is if you put an 8MM round in the chamber and the bolt extractor engauges and pulls the round out you don't need to check it with a 'go gauge' but just a 'no go gauge'.
Some will tell you, and I admit I've done it, you can take the gun out in the boondocks.....load it up, place some blankets, etc over it, weigh it down and pull the trigger with a string while you're around side of you vehicle.
If the gun is still intact afterwards ALL this tells you is after THAT shot it's still all together. It doesn't tell you if you were lucky or if it might go 'boom' in your face the next time. So, I DON'T recommend or subscribe to that method of testing.
The gauges can be purchased from various websites and are a good investment, especially if you plan on buying other 8MM surplus rifles.
After I post this I will research for the websites where you can buy the gauges, if you wish. Keep in mind the delivery time and the amount of time you might have left to purchase the guns.
If you have some local gun shops there might be one where you can buy the guages locally.
If the buyer insists he/she has had the guns gauged have him sign saying that and let your conscience be your guide. Have which ever you buy rechecked though. If they don't check out you might have some leverage making him take the gun back for another one.
Unfortunately, there are few people out there that will warranty their guns and most people sell on the pretense the buyer is supposed to know what they are shopping for and they buy 'as is'.
Incidentally, for about what he is asking for those guns you can buy an unissued Yugo M48 or M48A, and from firsthand experience, those are two super guns in their own rights.
But, for collectors, the German Ks are the ones to get...ones with the Nazi markings still intact, that is....otherwise the Germans with ground off markings are not that collectable.
Check out
www.brownells.com for the gauges and type in 'go gauge' in the search field.
I hope this is of some help to you and I haven't 'cornfused' you. If not, let me know and I will try and muddy the waters even more for you, lol.