Nice Haul Ras! Are the buildings and trees part of the haul too, of stuff you already had?
Regarding the actual age/generation of the knights, from what I can see I'd say they're 3rd generation - but we have to clarify what we mean by generation.
Here's my suggestion, open to correction or clarification:
1st Generation knights (1974) have chrome bodies & accessories (e.g. weapons, bullet shaped helmets and crowns) and non-turning wrists. (e.g. set 3269)
2nd Generation knights (1977) have coloured bodies with clip-on chrome armour, chrome accessories and non-turning wrists. Helmets were more detailed (e.g. sets 3265, 3291)
3rd Generation knights (1983) have chrome armour & accessories and turning wrists, (e.g. set 3905). From now on they all have turning wrists.
4th Generation knights (1986) have all black bodies and non-chrome armour, but still some chromed weapons. (e.g. set 3329) From now on chromed armour is dropped (except for the anniversary releases, Silver & Gold Knights on horseback).
5th Generation knights (1993) with front or back printing, non-chromed weapons, and detailed two-colour leg mouldings sometimes with printing (e.g. sets 3668, 3669, 7123, 3659, 7664) Some sets mirror previous compositions, with new mouldings and printings (as 3669 mirrors 3329). A Golden year for Knights with many new sets and the 3666 large castle.
6th Generation knights (2004) have armour moulded into their arms. (e.g. sets 4436, 5815)
I'm trying to identify major steps forward in design - e.g. did leg printing happen at the same time as the new leg moulds? If so that's only one generational step. I've added year of first appearance (in Germany) to the generations.
Not all knights currently manufactured have moulded armour for their arms, but I count this as an evolutionary step forward, not necessarily to everyone's taste.
Your figures are 1982 or later, as they have turning wrists. If you dare to pop one open you can see if it's 1986 or later, when the chassis was redesigned to its current form but the legs were still the basic style. I'm not sure if this counts as a generational step, because it doesn't alter the outward appearance of the figures, and may have happened at the same time as another evolutionary step.