If I were doing that route, and had the time, ie nothing planned, for the rest of that day of the flight, and would not mind (in the end, if it comes to it, being relegated to the 737/330), I would pay to go the 787, wider windows are a plus in my pov.
Granted of course, the 787 could easily be swapped to a 737/330, if that 787 goes techo (technical fault that would prevent it from continuing PER - MEL), but...
Go the 787 first, book with that.
Then if they have to swap it, at least you have nothing planned for the rest of the day, so to speak.
You will have to go T3 to check in with photo id, and get orange sticker, and surrender your BP at the end of the flight in MEL T2 though, so no souvenirs of the BP is possible, unless you take a photo of it on your smartphone.
Not sure if a person flying PER - MEL only, can do OLCI as you have to provide id as its an international flight, or you might be able to do provisional OLCI, and go to a desk at PER T3 to show id. and get the paper BP.
I have done several 787s flights, with JQ and LA(TAM), can't complain, as I said, I am a fan of wide windows.
Edit: as we know, if you usually get QP/J lounge access, you would have to go to go to PER T4 QP/PER J lounge instead of T3 transit J lounge.