It doesn't have the same effect, no.
G.INP (ITU-T G.998.4) is only available on ADSL2, ADSL2+ and VDSL2.
There is no "G.INP" on G.Fast.
It's called Retransmission (RTX)
Retransmission is part of the G.Fast spec (ITU-T G.9701) so is on by default at all times.
Some limited live/historic G.Fast stats if anyone wants a look
http://browni.co.uk/dslstats/Webserver/fullstats.htm
The images are taken from DslStats which isn't quite setup for G.Fast so many graphs don't show correctly.