Don't be misled into paying for an "antique" item which turns out to be far more recent in manufacture than claimed.
Over the years I have bought a number of hallmarked silver and gold items (mostly rings) which turned out NOT to be anywhere near as old as the seller described.
There are plenty of guides to hallmarks which are well worth taking the time to read, but the key point is this; all assay offices show the date of assay by means of a letter. Obviously there are only 26 letters so, every 26 years or so, they had to be repeated. The difference was in the style of lettering (the "font"), or a change from upper to lower case, but certain letters are hard to distinguish even in different styles - z being one of the worst.
So, there are certain dates which can be ambiguous unless you have a lot of experience. Sadly some sellers exploit this fact. Only once have I known a seller mis-date an item later than its actual date. Mostly they mis-date earlier. One hestitates to claim "fraud", but people are always keen to believe the best.
It is hard to be certain sometimes, as I say, z can be a nightmare, but I recently bought a ring advertised as 1876 - the date letter being "A". When it arrived, it took me less than a minute with a loupe magnifier to realise that the particular "A" on this ring meant that it was made in 1975. A BIG difference. Now, to be fair, the style of the ring was old and at first sight it could have passed for Victorian, but, had the seller photographed the hallmark clearly I would have seen from the picture that it was not as old as claimed. And, incidentally, the difference in style of these two "a"s left absolutely no room for doubt. It was NOT Victorian.
My advice is:
1) If a hallmark is not shown clearly, be cautious. Most of the mistakes I made had out-of-focus pictures.
2) If there's no 'photo ask the seller to describe the mark in detail and then check it against a good reference book - there are plenty of them.
3) If it doesn't look as old as its claimed, it almost certainly isn't.