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Judging from this, I would say yes:
"Graphics Cards
EVGA will only release reference versions of its products, NVIDIA reference spec and clock, to the Step-Up program. On occasion, EVGA may choose to make other select cards available.
Step-Up is limited to pre-approved graphics cards only and can only be used for exchange to a different and higher performing GPU.
Products known to have a limited availability will not be made available to the Step-Up program. (Limited availability determined by EVGA.)
Customers who received their EVGA graphics card as part of a complete computer system are not eligible at this current time. (We anticipate confirming approved system vendors in the near future.)
Graphics Cards Examples:
GTX 780 Ti → GTX 980: YES (Upgraded GPU)
GTX 960 2GB → GTX 960 4GB SuperSC ACX2.0+ 1GB: YES (Upgraded Memory)
GTX 970 FTW → GTX 970 FTW+ : YES (Upgraded Model)"
980ti to 1080 is the same as 780ti to 980, so I don't think there is an issue.