Yes, taht´s true,but I think other than in Ramesses II times, we have other historical sources than the pharao himself (It´s an inscription, when I recall correctly, proclaiming a victory), that was available to the Egyptian "populace".
At least Plutarch wrote about the battle in his live of Pyrrhos, and he is technically no Roman, eventhough being a citizen of the empire. Of course he is rather late, but he must have had his sources, for example Dinonysios of Halikarnassos, again a Greek. I think it would be quite difficult for the Romans to influence all the other traditions, since there surely were Epirote/Greek survivors of the battle as well. I´m not saying that it isn´t possible, I only think, there is again no proof, which would speak for Bleicken´s thesis. At least it wasn´t a clear enough victory, maybe anoter "pyrrhic" one, since Pyrrhos left Italy shortly after, abandonig his campaign.
But of course there may be some source I just don´t know, I didn´t put that much research into it :)