Steve, that's just conjecture from me on A-84 production. I have 3082 documented as a Gen3 (single gusset), and then, 3100 documented as an A-84. The Gen4 gusset frames got a GXXX SN, so, this is my speculation on SN continuation on the numbers, with only 18 numbers missing. So, I'm pretty comfy my start number is really close. I just don't know how high they went.
The actual spread on A-84 numbers I have is quite small, so, 200 could be high, but, the counts of frames on the later models I have SN's on is so small, that it's tough to do much more than make a logical guess, which is what 200 is, a logical guess. Someone could turn up an A-84 tomorrow with a much higher SN than mine and I'd have to revise that estimate.