It depends on what they come up with.
Amnesty with Reagan (as mentioned earlier in the thread) ended with Green Cards and permanent residency. In this case... Not so much.
If we wind up with folks getting temp visas to come here and harvest then it won't be any form of amnesty. If, as they have been saying, they are focusing on folks that have broken more laws than just crossing and sending those folks home first... Not going after farm workers seems to be within that purview.
I will wait to see what we wind up with. If it were me, they'd have to go and apply at the border for a temporary visa or they would face deportation. I wouldn't be hassling farm workers though, I'd be focused on drug traffickers, and human traffickers... once we've cleaned that up I'd then turn to the farms, by that time they'd have had plenty of time to get back across the border to apply for a temporary visa.