OK, I've looked it up in Krause. They did issue a multi-year proof set sometime after 1969, with most of the coins dated 1966, the large silver 500 fils dated 1968 and the 250 fils dated 1969. If your coins have dates other than those, they've been swapped out for non-proof coins.
They also issued an identical set in 1983, with all coins made of sterling silver and dated 1983. The eBay set clearly isn't the sterling silver set, since the three coins at the bottom are copper-coloured.
I'd say describing it as "Proof set 1966-1969" should be adequate.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis