Circuit Protection - Difference between two gas discharged tubes that are spec'd the same?
I would be concerned because the datasheet that digikey points to says 90V DC spark-over while digikey's description says 90V for the EPCOS device. So if we go based on the datasheet for the EPCOS component and compare it to the TE that you show the DC spark-over is now 500V which means that your device might have to withstand the higher voltage. However, in the same TE datasheet it shows the  GTCX26-900M-R05 part with an 90V DC spark-over that might be more appropriate. At this point I would contact EPCOS and Digikey and find out the actual DC spark-over voltage device since there seems to be a discrepancy.