Not really - you'll not notice much difference, but don't hammer it like a 20 mile ride..OK
PS 120 miles in a day is enough for me, but it was done (pre-broken back) in 6 1/2 hours ride time. Quick refill half way. It's not a great way to enjoy it - Sportive.
Post busted back...... very different...
I can ride on my own for about an hour before pain kicks in really bad at 'solo training pace' - like a ninja sticks a knife i your back - I can manage for about another hour with stops and stretches. on a MTB (not my Road bikes). Go out with a few MTB'ers of mixed ability, I can manage much longer - I can go up, but I can't go down quickly. The waits, or not 'riding too hard' allow recovery - stretch...
I'd just taper your miles again, and make sure you have a few long distance rides before (100 plus). I used to do 100 mile sportives on a 25 mile a day commute training.
You'll smash it - I'd never get near that miles again, so go for it. !!!