The direction of resampled tck file


I am currently running ROI to ROI tractography and want to fit the FA map onto the tracts, just like this Resampling.

I generated tracts from LGN to V1 and from V1 to LGN using tckgen, and then the two tck files were concatenated into a single tck file. I now would like to resample the tck file and analyse the FA along the concatenated tck file. I use tckresample command with the flag -numpoints 100, and then use tcksample to generate the mean FA in each node. I now have a txt file containing all FA values of 100 nodes in each streamline. However, I’m not sure what would be the start and endpoint of the concatenated tck file, would this be the same as the first tck file (LGN as the start and V1 as the endpoint)? Is there a way to check this?