The year won't make any difference, in this case. An Imrie/Risley Hessian grenadier cast today is worth the same as one ordered today.
Some of the Hellenic figures are worth more, because they are out of production. Hellenic Miniatures was Bill Imrie's first venture, named for his wife, Helen. She's still running the business. For example, there is a figure of a Prussian hussar, cast in a single piece, based on an illustration by Adolph Menzel. It sells for anywhere from five to ten bucks.
I think you'll find that these will sell, because there are guys who want to paint them, but I don't think you'll be able to get anything more for castings that are older. I would try selling them at $10 apiece, but you should go to eBay and follow some I/R auctions (I have a regular search for them) and you can get an idea of how much to ask.
Or, you could list the individual ones here, and let the feeding frenzy begin. ^&grin
Prost!
Brad