I'm having difficulty understanding what Van/Wagon model years determine what generation.
I have a 2000 Dodge Ram Wagon and I am trying to understand, is it 2nd or 3rd generation and does the generation affect interchangeability of parts?
Can someone break it down for me? And are the Van/Wagon generations matched to Ram Truck generation as far as model years?
I just mounted a 1994 van rear bumper on my 2000 wagon and 6 of the 8 bolts lined up. It's good enough. But is it what I should expect as for variation in trim parts?

 

https://en.wikipedia.org/wiki/Dodge_Ram_Van

 

After the A-series vans, with their solid front axle and mid-mounted engines, the B-series came out in 1971. There was a change in frontal sheet metal in 1979 and then the later rounded front of the more distinctly 'RAM' bodywork appeared in the nineties and ran to 2004. With that last change came a movement of the engine forward by about 2", but otherwise the platform and suspension remained basically unaltered for the whole period.

Another change I know of was an increase in front wheel bearing size, at least in the B350s, some time during the eighties.