OK, after doing some searching I've found a document, from Sean in PA I think, clears up the DD314K DD3=545, 1=diesel, 4=Independent 540 PTO, K=6x4 manual reversing.
I'm pretty pumped about Ind PTO! We haven't tried it yet without the clutch being depressed, just wanted to find out for sure to prevent unnecessary grinding.
Still no clue on everything else. A few people have mentioned the 545 S/N would fall in with the 4610s sequencing.