Originally Posted by
noglider
The choice of tubing wasn't random. According to my unreliable memory, there was at least one threesome of models that differed only in tubing because some people thought it made more of a difference than it really does. Some wanted Columbus or Reynolds because they believed one of those was best, and some wanted equivalent but to save a little money. So Trek provided.
Yes, I agree completely and your memory has it right - the frame models were mostly only different in terms of tubing brand and paint, and hence price. I strongly doubt Trek badged a Reynolds frame as an Ishiwata, and vice versa. If a person tries to use SN to identify what model a frame is (not what geometry), we should not be saying a 710 could be made of Magny.
My hypothesis was that it's a repaint and correct decals were not re-applied, but the conclusion it's a 311 is a simpler explanation - Occam's Razor.