I just got off the phone with a Honda rep, and recorded it btw, who said his cut off was 1986 but parts for '87s may have gotten out at some point very early in the production runs before complete trikes were actually put together to be shipped off. No complete trikes were ever actually built or sold, so he couldn't give me any production numbers when he dug into them. He said most of the guys who would know this information are now retired. He also gave me numbers for Honda Canada and Honda Japan to see if they could dig up any information on them when I asked if they may have been sold overseas or in other countries. I'll try and give them a call soon.
So no. The 1987 250R or 350X do NOT exist [This was later confirmed to be false to an extent), but pre production parts got out and/or were sold off early in the production runs, which would explain miscellaneous parts such as the random seat, cylinder heat and plastics but no full trike. I'll have the video uploading soon. This is for the US.
In Canada, they were sold in extremely low numbers and were confirmed to exist. I have that recorded as well.
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EDIT:
After some time, the search continues. Credible evidence will hear on out be posted in this thread.