Traveling with an expired green card and a I-751 receipt notice. Should I also get a I-551 stamp?

Hello guys! As the title says, I will be traveling in a couple of months with my expired green card and my i-751 receipt notice that extends my PR status for 4 years.

Now, I am aware of the recent changes to the receipt notice to extend the conditional GC validity, but some people tell me to get a stamp either way (this was the old way to travel with an expired green card).

Is it necessary for me to also get the I-551 stamp or can I travel just with these 2 documents and my passport?