I was reading some old Observers from 1986 last night and came across the following in the 02.24.86 issue,
"Newcomers to the WWF at recent TV tapings are Jake Roberts, Dory Funk Jr, Trapper John (John Harris) and Alexis Smirnoff."
Meltzer doesn't say what tapings he debuted at and he seemingly quit a month or so after this debut match despite being on the payroll for a while before. My guess, and this is only a guess, is that his try-out match/debut was in a dark match at the 01.28.86 Poughkeepsie tapings.