I have a similar problem with my collection. I sometimes buy a pedal without realizing I already own it. Now that I've started pulling my cases out and start organizing my collection a bit better, I'm running into some doubles. I'll have to start selling some soon to make room for some others.
Perhaps I should add a link to my geeky Excel sheet that I use. Whenever I get a new pedal I mark it with a different colour to make sure I know which ones I have.
that's no problem about not including the supposed 'black label' Boss EH-2 that recently sold on eBay -- it made me do a double-take myself. hopefully the person who bought it will be equally curious and decide to open it up to see if the circuitboard is also marked 'Japan', or if there is other extenuating evidence. but you're right, it's probably not original.
and let me know if you'd like scans of my CE-5 (dark grey/Taiwan) or SD-2 (silver/Taiwan). thanks again!
That actually reminds me of something strange that I've experienced when opening up a few pedals. I have actually had pedals with MIT bottom plates and MIJ PCBs. Could be the same thing, where someone replaces the plate with the wrong one. It's kind of a nice little surprise though, finding out that it's actually a MIJ pedal!