There is zero indication that Neal Cassidy is supposed to be Baelfire, and given Bael's prominence in things vis a vis Rumple, it doesn't make sense for there not to have been even the slightest of hints dropped if he were to in fact be Rumple's son under a different name.
I think that there is indication that can be inferred. The episode where we found out Bael was lost in another world was inference enough. Henry's father is either some random white guy from somewhere in America, or he is Bael. The random white guy we met is a guy who had no roots, no family, would steal in a heartbeat, yet was capable of true love, loyalty, and had more than a pocketful of ethics. His character description alone marks him.