I hear where you are coming from and it is a difficult one to comment on - you did try to find out if it was a route, it wasn't recorded, so honest mistake etc.
But it was either an existing or something that some one had tried or something, or else why was the bolt there. Would you have tried it the way you did if the bolt was not there? Would you have gone ground up ? If you bailed would you have rapped in to suss it out? etc etc etc I guess we will never know because the bolt was there. I know a bolt on a face can be inviting, and also that blank faces can seem intimidating.
I agree that you did it in fine style; up to the point where you used a sign-post bolt to indicate where the route goes, not sure about that bit.
Simey makes some good points but I'm not sure he really nails it. Times have moved on - climbs attempted are harder, and less obvious, more dangerous.
Sometimes on hard/bold it is basically 'saner' to rap and have a quick look at something to make sure you do at least stand a chance and its not suicidal.
I wrote a whole lot more to try to explain but it all gets too wordy and convoluted - making decisions about doing bold climbs can be a real mind-fcuk sometimes.
I have sometimes spent ages/years working myself out in order to approach certain climbs - just making the decision to seriously consider doing it can be bloody hard . . .