I'm not sure. I'll have a look for you...
Edit: I don't think there is, they only added the vanilla game to PS Collection I believe. Yeah only way to get it is if you buy the new game. Royal is an expansion on top, like DLC. There is some changes to the base game, mostly optimisations to make it easier, with new characters and another arc added. It depends if you're interested in all that. It's £27.50 now on PS Store. Persona 5 is already an universally lauded game, so not playing Royal won't break your experience at all in my opinion. That's the one I played, and it was excellent.