Probably not, though I'm sure some of the Japanese releases saw some minor bug fixes on some games, though I wouldn't hold my breath for a total overhaul of Suikoden to include a new script and the additions from Suikoden 1 & 2 on PSP.
Though, you never know. Since the game is only slated as PS3/PSP, it still doesn't confirm that the game is definitely going to be a PS1 Classic release. It could very well be the updated version and will be sold for a higher price than the average classic game on PSN, though I wouldn't bet on it.
On that note, I guess the complete lack of info on CERO's website means the game might not be coming to Japan for a small while. Probably because they already have Suikoden 1 & 2.
Formerly known as: Gothann