You picked one of the most complicated guns to try to buy. First is is not even in the US. Then you have to learn how to import it if you win the auction. If it is a bust you have almost no real chance to send it back, read the fine print. This is a bad crap shoot for one of the self appointed experts and a real adventure for one like yourself. I am not trying to pick on you.
In fact if I wanted to run a scam I would do so from overseas. Real hard for someone to find me and get their money back or to punch me in the nose. This seller looks as good as they get with almost 300 feedbacks and not one bad gripe. Not many dealers like that on the auction sites.
First buy only guns that you get to examine in person. The internet, for a new buyer, is almost the worst place for you to buy a gun. Go to a gun shops or visit several gun shows. Take someone along who knows what they are doing when you go to look at a gun. Do not fall in love with any gun. If you fall in love you will not note all the warts and dents that you must see when buying. Do not buy any fixer uppers.
Find either a nice shooter or a high condition newer gun to start with. Like trains, guns are not to be limited to the first one you see. They made thousands of them and another one will be along soon. So set a hard dollar limit for your first buy and wait until you find the right gun.
If you want a foreign gun do some research into them. Limit your search to one country or one maker. Far easier to become fluent in one gun maker than an entire group of makers. Have you looked at Darnes as a starting point. Solid built guns, lots of information and they are just different enough to be interesting to all who see them.
The gunbroker gun has a lot of external wear and grime. Is it pitted both on the surface and in the bores like the photos look like? Condition is not that great from what I can see. Engraving impresses us a lot because it is very expensive in todays cost but most guns were engraved for just a few dollars when made. Some of the best British guns cost less than three pounds to engrave when made. Fifteen dollars in the then current exchange rates of 1900. That was for full scroll work of the highest level. I would keep looking for now.