Infect combo question

I've read that once a permanent gains a -1/-1 counter from infect, it stays on it indefinitely, even if it were to be put into a graveyard and then back into the battlefield at some later point. Is this correct? If so, please continue reading.

Lets say target opponent has 1 poison counter on him/her, and that mana is not an issue.
Now lets say...
I have a core prowler on the battlefield. I cast 2 contagion clasp's. I apply the 2 -1/-1 counters to the core prowler sending it to the graveyard and activating it's proliferate ability. I then cast a corpse cur, which by entering the battlefield activates it's ability and returns target creature with infect from my graveyard to my hand. So I return the core prowler to my hand. Then I cast the core prowler.

Since it still has the 2 -1/-1 counters on it, it will be sent to the graveyard and it's ability will activate again to proliferate.

So target opponent now has 3 poison counters due to the core prowler proliferating twice.

Is this correct?