Originally Posted by
steinrr
Yes, there is a Sora front derailleur fitted today, but since the chain line is 50mm (which is typically MTB) instead of 45mm, I suspect that they've done some special modifications wrt the bottom bracket to make it work. So I am not confident that the shifters are road type....
The difference in Road vs. MTB front shifters is the amount of cable pull between the clicks. The MTB front shifter pulls more cable and thus only works effectively with matching FDs. So, if your current shifter indexes properly with a road FD, it probably is a road shifter and will work with a FD-3503.
About you current crankset chainline, it may be that a non-spec BB was installed or the bottom bracket shell was built slightly offset to the right on the frame. Either of these may have been done for some reason, (crank/stay clearance, wider rear hub OLD, ?...).
Most FD have some leeway in the total range that is available and should be fine even if the new crankset is slightly outboard of spec.