This is Robert here and I would be happy to help with your International Silver flatware set. It sounds like it's the real thing.
Could you very kindly re-attach the photo, the link doesn't seem to be working.
If you could give me a rough inventory of the set and a photo of the mark and one of the pieces so I can see what pattern this is, I'll be able to give you an accurate re-sale value.
Thanks, ***** ***** came through just fine. That's just what I needed to see.
Leave this with me and I'll have a full answer and a value for you as soon as I can.
The pattern name for this flatware set is called "Yorkshire Bead-Gold Plated". It was issued by The International Silver Co. from 2000-2003 and is now discontinued. However there does seem to be a reasonable demand for this pattern on the secondary market, in other words, at auction sales and on line (eBay, Amazon, etc) which is by far your best option for selling.
The fact that you have the original canteen (fitted box) is a great plus and will make it more salable.
Looking at recent sales, this very similar example, but showing signs of light use, sold on line (eBay) for $150 which probably about right.
I would give yours an auction or on line value in the range of $140 - $200.
It therefore has a full replacement/insurance value of $400.
I do hope this helps!
Please let me know if I can be of further assistance with this, I would be glad to.