I recently got a bike that has no model or brand name on it. What would be the best way to go about trying to identify this bike? It's an old steel road frame with horizontal dropouts where the serial number is located on the non-drive side. I've already spent 3 hours googling images trying to match lug patterns and to see which bike manufacturers put the serial number on the dropouts, but to no luck narrowing it down. Any tips or help is appreciated.