As an uninvolved party I'd say " I'll take it" trumps "very interested".
So, the next time I have additional questions or want to see additional photos, I should go ahead and say "I'll take it" and then when those additional photos and information show that I don't really want it, I back out?
I agree with what you are saying if the original ad is complete in description and photos, and the condition is shown, but in this case this is a one off custom seat.
I passed because I was interested in the seat, not the pan, but then realized it would not work for me.